Non-aqueous electrolyte secondary battery

ABSTRACT

The present invention provides a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode having a negative active material, and a non-aqueous electrolyte, characterized in that the negative active material contains composite particle (C), which has silicon-containing particle (A) and electronic conductive additive (B), the silicon-containing particle (A) has a content of carbon, and when measured at a temperature rising rate of 10±2° C./min by thermogravimetry, said composite particle (C) exhibits two stages of weight loss in the range of 30 to 1000° C.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional of Ser. No. 13/187,550 filed Jul. 21, 2011, whichis a divisional of application Ser. No. 10/513,664 filed Nov. 8, 2004,now U.S. Pat. No. 8,092,940, which is the National Stage ofPCT/JP03/05654 filed May 6, 2003; the above noted prior applications areall hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a non-aqueous electrolyte secondarybattery.

BACKGROUND ART

In the past, carbon material has been used mainly as a negative activematerial for lithium-ion secondary batteries.

These days, however, in the batteries which utilize carbon material as anegative active material, the discharge capacity is so enhanced as to beclose to the theoretical capacity of carbon material. Such a presentsituation makes it difficult to further improve the discharge capacityof those batteries.

In recent years, therefore, high-capacity negative active materialswhich can be alternatives to carbon material have been studiedthoroughly. As one example of such high-capacity negative activematerials, silicon material can be included (refer to ProvisionalPublication No. 29602 of 1995, for example.)

With silicon being used as a negative active material, however, abattery significantly deteriorates in cycle performance compared to acase of carbon material being used as a negative active material. Thereasons for this can be explained as follows: having a large volumeexpansion associated with absorption of lithium ion, silicon ispulverized easily due to the repetition of charge/discharge; suchpulverization creates a portion where a conductive pathway is broken andcauses a decrease in current collection efficiency; and, consequently,as the number of charge/discharge cycles grows, the capacity decreasesrapidly and the cycle life becomes short.

As described in USP200210086211 and EP1205989A2, Provisional PublicationNo. 3920 of 1998, and Provisional Publication No. 215887 of 2000, it isproposed that a non-aqueous electrolyte secondary battery utilize thesilicon which is coated with carbon material, as a negative activematerial, in that the carbon material-coated silicon shows better cycleperformance than the one without coating.

However, as compared to a conventional lithium ion battery where carbonmaterial is used as a negative active material, the cycle performance ofthe above proposed battery is still unsatisfactory.

The present invention has been conducted in view of such circumstances.It is an object of the invention to provide a non-aqueous electrolytebattery having a large capacity and a satisfactory cycle life.

DISCLOSURE OF THE INVENTION

The present invention of claim 1 provides a non-aqueous electrolytesecondary battery comprising a positive electrode, a negative electrodehaving a negative active material, and a non-aqueous electrolyte;characterized in that the negative active material contains thecomposite particle (C), which has silicon-containing particle (A) andelectronic conductive additive (B), and carbon material (D), and thatthe weight of the electronic conductive additive (B) falls within therange of 0.5 wt. % to 60 wt. % to the weight of the composite particle(C).

According to the present invention, the said negative active materialcontains the composite particle (C), in which the silicon-containingparticle (A) and the electronic conductive additive (B) are contained,and the carbon material (D), and hence the cycle life improves. Thereasons for this have not been determined yet clearly; however, it isvery likely that the presence of the electronic conductive additive (B)and the carbon material (D) causes the enhancement of the contactconductivity between the silicon-containing particle (A) and between thecomposite particle (C), respectively.

In addition, the weight of the electronic conductive additive (B) fallswithin the range of 0.5 wt. % to 60 wt. % to the weight of the compositeparticle (C), and hence the discharge capacity and the cycle performanceimprove. If the weight of the electronic conductive additive (B) is lessthan 0.5 wt. % to the weight of the composite particle (C), the amountof the electronic conductive additive (B) becomes insufficient to theamount of the silicon-containing particle (A), so that inadequateelectronic conductivity causes the deterioration of the cycleperformance. Meanwhile, if the weight of the electronic conductiveadditive (B) is greater than 60 wt. %, the discharge capacity per activematerial weight is reduced and, consequently, the battery dischargecapacity becomes small.

The present invention of claim 2 is characterized in that, in thenon-aqueous electrolyte secondary battery of the present invention ofclaim 1, the silicon-containing particle (A) has a content of carbon,and that the composite particle (C) is configured by coating thesilicon-containing particle (A) with the electronic conductive additive(B).

According to the invention of claim 2, the silicon-containing particle(A) has a content of carbon, and hence the contact conductivity ofsilicon becomes better and this results in improvement in the cyclelife. In addition, the composite particle (C) is configured by coatingthe silicon-containing particle (A) with the electronic conductiveadditive (B), and hence the cycle life improves. It is believed that thereason for this may be that since the particle (A) is coated with theelectronic conductive additive (B), even when the active material ispulverized due to the active material expansion/contraction that occursduring charge/discharge, the deterioration of the contact conductivityis prevented.

The present invention of claim 3 is characterized in that, in thenon-aqueous electrolyte secondary battery of the present invention ofabove stated claim 1 or claim 2, the proportion of the weight of thecomposite particle (C) to the total weight of the composite particle (C)and the carbon material (D) falls within the range of 60 wt. % to 99.5wt. %.

According to the invention of claim 3, the proportion of the weight ofthe composite particle (C) to the total weight of the composite particle(C) and the carbon material (D) falls within the range of 60 wt. % to99.5 wt %, and hence the discharge capacity and the cycle life improve.If the proportion of the weight of the composite particle (C) to thetotal weight of the composite particle (C) and the carbon material (D)is less than 60 wt. %, the negative active material becomesinsufficient, so that the discharge capacity decreases. If theproportion of the weight of the composite particle (C) is greater than99.5 wt. %, the contact conductivity between the active materialdeteriorates, so that the cycle life is reduced.

The present invention of claim 4 is characterized in that, in thenon-aqueous electrolyte secondary battery of the present invention ofabove stated claim 1 or claim 2, silicon oxide SiO_(x) (where 0<X≦2) iscontained in the composite particle (C).

According to the invention of claim 4, silicon oxide SiO_(x) (where0<X≦2) is contained in the composite particle (C), and hence the cyclelife improves. It is believed that the reason for this may be thatchanges in volume during charge/discharge are smaller in silicon oxideSiO_(x) (where 0<X≦2) as compared to those in silicon.

The present invention of claim 5 is characterized in that, in thenon-aqueous electrolyte secondary battery of the present invention ofabove stated claim 4, the proportion of the weight of the compositeparticle (C) to the total weight of the composite particle (C) and thecarbon material (D) falls within the range of 1 wt. % to 30 wt. %.

Since the discharge capacity decreases, it is not preferable that theproportion of the weight of the composite particle (C) to the totalweight of the composite particle (C) and the carbon material (D) be lessthan 1 wt. %. In addition, it is not preferable either that theproportion of the weight of the composite particle (C) to the totalweight of the composite particle (C) and the carbon material (D) begreater than 30 wt. %, since the negative active material significantlyexpands and contracts during charge/discharge and, as a result, thecycle performance deteriorates. It is more preferable that theproportion of the weight of the composite particle (C) to the totalweight of the composite particle (C) and the carbon material (D) fallwithin the range of 5 wt. % to 10 wt. %.

The present invention of claim 6 provides a non-aqueous electrolytesecondary battery comprising a positive electrode, a negative electrodehaving a negative active material, and a non-aqueous electrolyte;characterized in that said negative active material hassilicon-containing particle (A), and that said silicon-containingparticle (A) contains silicon oxide SiO_(x) (where 0<X≦2) and carbon.

According to the invention of claim 6, silicon oxide SiO_(x) (where0<X≦2) is contained in the composite particle (C), and hence the cyclelife improves. It is believed that the reason for this may be thatchanges in volume during charge/discharge are smaller in silicon oxideSiO_(x) (where 0<X≦2) as compared to those in silicon.

In addition, carbon is contained in the composite particle (C), andhence the cycle life improves. The reason for this is that even whensilicon or SiO_(x) is pulverized during charge/discharge, a conductivepathway is kept by carbon, so that a decrease in the current collectionefficiency can be inhibited.

The present invention of claim 7 provides a non-aqueous electrolytesecondary battery comprising a positive electrode, a negative electrodehaving a negative active material, and a non-aqueous electrolyte;characterized in that the negative active material contains thecomposite particle (C), which has silicon-containing particle (A) andelectronic conductive additive (B), that the composite particle (C) hasa content of carbon, and that when measured at a temperature rising rateof 10±2° C./min by thermogravimetry, the composite particle (C) exhibitstwo stages of weight loss in the range of 30 to 1000° C.

According to the invention of claim 7, the composite particle (C) has acontent of carbon and when measured at a temperature rising rate of10±2° C./rain by thermogravimetry, it exhibits two stages of weight lossin the range of 30 to 1000° C., and hence the cycle performance isimproved. The reasons for this can be explained as follows. Weight losshardly occurs to silicon at a temperature range of 30 to 1000° C.;therefore, it is carbon that causes weight loss in such a temperaturerange. Carbon, depending on the different properties, will differ in thetemperature at which weight loss starts. In the present invention,therefore, at least two different kinds of carbon should be contained inthe composite particle (C). And containing different kinds of carbon inthe negative active material allows the silicon expansion/contractionthat occurs during charge/discharge to be reduced and, consequently, thecontact conductivity in the particle of the negative active material canbe retained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing TG measurement results.

FIG. 2 is a view showing the cross sectional configuration of aprismatic battery used in Embodiment A.

FIG. 3 is a view showing the cross sectional configuration of aprismatic battery used in Embodiment B.

FIG. 4 is a schematic view showing the cross section of a compositeparticle used in Embodiment C.

FIG. 5 is a schematic view showing the cross section of a compositeparticle used in Embodiment C.

FIG. 6 is a schematic view showing the cross section of a compositeparticle used in Embodiment C.

FIG. 7 is a schematic view showing the cross section of a compositeparticle used in Embodiment C.

FIG. 8 is a view showing a mixture of carbon material (D) and compositeparticles (C).

PREFERRED EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to the accompanying drawings.

As a negative active material in the present invention, it is possibleto use a material which contains the composite particle (C), in whichsilicon-containing particle (A) and electronic conductive additive (B)are contained, and carbon material (D).

As the silicon-containing particle (A) in the present invention, it ispossible to use, for example, the following particles: silicon particle,silicon oxide particle, or the silicon particle or silicon oxideparticle which has at least one element selected from the groupconsisting of the typical nonmetallic elements such as B, N, P, F, Cl,Br, and I; the typical metallic elements such as Li, Na, Mg, Al, K, Ca,Zn, Ga, and Ge; and the transition metallic elements such as Sc, Ti, V,Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, and W. These may be usedalone or in combination with two or more.

As the electronic conductive additive (B) in the present invention, itis possible to use, for example, Cu, Ni, Ti, Sn, Al, Co, Fe, Zn, Ag oralloy of two or more of these elements, or carbon material. Among these,it is more preferable to use carbon material.

Regarding the methods of coating the particle (A) with carbon materialas the electronic conductive additive (B) in the present

invention, the following techniques can be used. In CVD method, benzene,toluene, xylene, methane, ethane, propane, butane, ethylene, oracetylene, as a carbon source, is decomposed in gaseous phase andchemically deposited on the surface of the particle (A). In anothermethod, the particle (A) is mixed with pitch, tar, or thermoplasticresin (for example, furfuryl alcohol) and then calcinated. And inanother method, a mechanochemical reaction is used, where mechanicalenergy is applied between the particle (A) and the carbon material withwhich the particle (A) is coated so that a composite can be formed.Among these methods, because of the uniformity in the carbon materialcoating, it is preferable to use CVD method.

When Cu, Ni, Ti, Sn, Al, Co, Fe, Zn, or Ag is used as the electronicconductive additive (B) in the present invention, it is possible to use,for example, CVD method, spatter evaporation method, or plating method.

In the present invention, it is preferable that the proportion of theweight of the electronic conductive additive (B) to the weight of thecomposite particle (C) fall within the range of 0.5 wt. % to 60 wt. %,more preferably in the range of 1 wt. % to 60 wt. %, and even morepreferably in the range of 5 wt. % to 40 wt. %. If the proportionexceeds 60 wt. %, a large discharge capacity cannot be attained. And ifit is less than 0.5 wt. %, the contact conductivity of thesilicon-containing particle (A) deteriorates and, as a result, the cyclelife is reduced.

In addition, as the electronic conductive additive (B), carbon materialin a variety of crystal forms can be used. Especially, it is preferableto utilize the carbon material that has 0.3354 to 0.35 nm in the averageinterplanar spacing d (002), which is obtained by conducting X-raydiffraction on the carbon on the particle (A). Within such a range, itis possible to attain a large initial discharge capacity and a highcapacity retention ratio according to cycle. The measurement of d (002)can be carried out using, for example, a X-ray diffractometer RINT2000(Rigaku) with the use of Cukα radiation.

The average interplanar spacing d (002) of the carbon material which isused as the electronic conductive additive (B) in the present inventioncan be adjusted in the following manner. For example, when the particle(A) is mixed with thermoplastic resin and then calcinated, the distancecan be adjusted by means of a calcination temperature. In addition, whenthe particle (A) is coated with carbon using CVD technique, it can beadjusted by means of a CVD temperature. It is preferable that theaverage interplanar spacing d (002) lie in the range of 0.3354 to 0.35nm: for example, when a large value of approximately 0.35 nm isdesirable, a calcination temperature or CVD temperature can be set atapproximately 1000° C., and when a small value of approximately 0.3354nm is desirable, a calcination temperature or CVD temperature can be sethigher than approximately 1000° C. and not higher than approximately3000° C. With a processing temperature being set lower, the averageinterplanar spacing d (002) tends to be larger. In order to keep theaverage interplanar spacing d (002) as small as possible, with aprocessing temperature remaining low, the carbon can be made to grow onthe surface of the particle (A) as slow as possible using an organicmatter having a benzene ring such as benzene, as a carbon source forCVD.

When a mechanochemical reaction is employed as the compoundingtechnique, the average interplanar spacing d (002) of 0.3354 nm can beobtained by using natural graphite microparticle. Furthermore, it ispossible to attain the average interplanar spacing d (002) ofapproximately 0.346 nm by using the carbon particle which is prepared bycalcinating coke at approximately 1000° C.

Moreover, when silicon particle is used as the particle (A), thepreferable BET specific surface area lies in the range of 1.0 to 10.0m²/g. In addition, if the BET specific surface area of the compositeparticle (C) exceeds 10.0 m²/g when silicon particle is used as theparticle (A), undesirable results are generated as follows: bindingeffect between the active material by the use of a binder becomes lessstrong, the negative active material expansion/contraction duringcharge/discharge causes gaps to occur between the negative activematerial, the electrical connection between the negative active materialis broken, and as a result, the cycle performance decreases. Therefore,it is preferable that the BET specific surface area of the compositeparticle (C) be not greater than 10.0 m²/g. The BET specific surfacearea can be measured by using, for example, GEMINI2375 (SHIMADZU).

The BET specific surface area of the composite particle (C) in thepresent invention can be adjusted in the following manner. For example,when the particle (A) is coated with the electronic conductive additive(B) by means of CVD, by applying a large amount of coating, the BETspecific surface area can be reduced. Moreover, by controlling theparticle size distribution with the use of a sieve, the BET specificsurface area can be adjusted, too. More specifically, with an increasein the amount of the particle whose particle size is small, the BETspecific surface area becomes large, and with an increase in the amountof the particle whose particle size is large, it becomes small.

As the carbon material (D) in the present invention, it is possible touse one or more materials selected from the group consisting of naturalgraphite, artificial graphite, acetylene black, ketjen black, or vaporgrown carbon fiber. Concerning the shape of the carbon material (D), avariety of shapes can be used including spherical, filamentous, andscale-like shapes. Among them, because of its capability of fullysecuring the electronic conductivity, it is preferable to use thegraphite of a scale-like shape, the number average particle size ofwhich ranges from 1 to 15 μm. In addition, from the perspective ofimproving the cycle performance, meso carbon micro beads or meso carbonfibers, or the material prepared by adding boron to either of suchcarbon materials can be used.

Moreover, when the silicon-containing particle (A) has a content ofcarbon and the composite particle (C) is configured by coating theparticle (A) with the electronic conductive additive (B), the cycleperformance can further improve. Allowing for satisfactory cycleperformance, the preferable proportion of the weight of the componentother than carbon to the weight of the particle (A) falls within therange of 10 wt. % to 70 wt. %, more preferably in the range of 20 wt. %to 70 wt. %.

Furthermore, when SiO_(x) (where 0<X≦2) is not contained in thecomposite particle (C), the preferable proportion of the weight of thecomposite particle (C) to the total weight of the composite particle (C)and the carbon material (D) falls within the range of 60 wt. % to 99.5wt. %, in order for the cycle performance to improve and for thecapacity to be secured.

By using the composite particle (C) in which silicon oxide SiO_(x)(where 0<X≦2) is contained, more satisfactory cycle performance can beachieved. It is believed that the reason for this is that volumeexpansion can be inhibited because of the inclusion of SiO_(x). It ispossible to use Si particle and SiO_(x) particle by mixture, or theparticle which contains both Si and SiO_(x) (where 0<X≦2) phases mayalso be used.

It is preferable that the silicon oxide which is contained in thecomposite particle (C) have both Si and SiO_(x) (where 0<X≦2) phases.This is possibly due to the following reasons. In the material whichcontains both Si and SiO_(x) (where 0<X≦2) phases, lithium isabsorbed/desorbed in Si which disperses in SiO₂ matrix and, as a result,the volume expansion of Si is inhibited, so that the cycle performancebecomes excellent. Therefore, by mixing both phases at an optimalproportion, it is possible to obtain a negative active material having alarge discharge capacity and excellent cycle performance.

The material which contains both Si and SiO_(x) (where 0<X≦2) phases canbe obtained as follows. For example, when SiO is calcinated in N₂ or Arat a range of temperature from 900° C. to 1400° C., SiO startsseparating into Si and SiO₂ at approximately 900° C. and the separationis almost complete at 1400° C. In this case, when a larger amount of Siis desirable, the temperature can be set higher, and when a smalleramount of Si is desirable, the temperature can be set lower.

In addition, the material which contains both Si and SiO_(x) (where0<X≦2) phases can be identified in the following manner. First, Sipowder and SiO₂ powder are mixed at different ratios to prepare standardsamples. For these standard samples, NMR, measurement is performed toexamine changes in the Si and SiO₂ peaks at different mixture ratios.Next, for the material which contains both Si and SiO_(x) (where 0<X≦2)phases, NMR measurement is performed. By making a comparison between themeasurement result obtained and those of standard samples, the peaks ofSi and SiO₂ are identified, and furthermore the value of X for SiO_(x)can be obtained by determining the ratios of Si and SiO₂.

In the X-ray diffraction measurement conducted by the use of the CuKαradiation on the material which contains both Si and SiO_(x) (where0<X≦2) phases, it is preferable that at least one of the half widths ofthe Si (111)-plane and Si (220)-plane diffraction peaks be less than 3°(2θ). The reason for this is that when the material the half width ofwhich is not smaller than 3° (2θ) is used, the cycle performancedecreases. In addition, when silicon oxide is contained, in order tofurther improve the cycle performance, it is preferable that theproportion of the weight of the composite particle (C) to the totalweight of the composite particle (C) and the carbon material (D) fallwithin the range of 1 wt. % to 30 wt. %, or more preferably, within therange of 5 wt. % to 10 wt. %.

Moreover, the preferable proportion of the weight of Si to the totalweight of Si and SiO_(x) falls within the range of 20 wt. % to 80 wt. %.The reason for this is that since Si exhibits a larger dischargecapacity than SiO_(x), if the proportion of the weight of Si is lessthan 20 wt. %, the discharge capacity decreases; and that, on the otherhand, since SiO_(x) exhibits smaller volume expansion duringcharge/discharge and more excellent cycle performance than Si, if theproportion of the weight of Si is greater than 80 wt. %, the cycleperformance deteriorates.

Furthermore, when the particle (A) comprising silicon oxide SiO_(x) isused and carbon material is used as the electronic conductive additive(B), if the proportion of the carbon material contained in the compositeparticle to the negative active material is less than 3 wt. %, thefollowing undesirable result is generated: the particles consisting ofSi, the particles consisting of SiO_(x), or the particles containing Siand SiO_(x) are pulverized due to the repetition of charge/discharge,the breakage of conductive pathway caused by such pulverization cannotbe prevented, and as a result, the cycle performance deteriorates. Inaddition, the proportion being greater than 60 wt. % is not preferredeither because the discharge capacity is caused to decrease. Therefore,it is preferable that the proportion of the carbon material on thesurface of the composite particle to the entire negative active materialfall within the range of 3 wt. % to 60 wt. %.

In addition, among those composing the silicon-containing particle (A),the particle consisting of Si, the particle consisting of SiO_(x) (where0<X≦2), or the particle containing Si and SiO_(x) (where 0<X≦2) can beused in either highly crystalline or amorphous state: however, amorphousstate is preferable. The reason for this is that if the particle changesfrom a highly crystalline structure into an amorphous structure due tocharge/discharge, there is a possibility that electric potential of thenegative active material may vary. Therefore, in order to preventelectric potential variation from occurring during charge/discharge, itis preferable to use an amorphous structure in advance.

In addition, regarding the particle consisting of Si, the particleconsisting of SiO_(x) (where 0<X≦2), or the particle containing Si andSiO_(x) (where 0<X≦2), the following can also be used: the particleswhich have been washed with acid such as fluorinated acid or sulfuricacid, or the particles which have been reduced with hydrogen.

Moreover, from the standpoint of improvement in the cycle performance,when the silicon-containing particle (A) has a content of carbon, thepreferable proportion of the weight of silicon to the weight of thesilicon-containing particle (A) falls within the range of 10 wt. % to 70wt. %, or more preferably within the range of 20 wt. % to 70 wt. %.

In addition, when carbon material is used as the electronic conductiveadditive (B) for coating, the usable crystalline material ranges fromhighly crystalline graphite to low crystalline carbon. Especially,because of its low electrolyte-solution reactivity, it is preferable touse low crystalline carbon.

Furthermore, it is preferable that the number average particle size ofthe composite particle (C), which is configured by coating thesilicon-containing particle (A) with the electronic conductive additive(B), range from 0.1 to 20 μm. When the composite particle (C) isconfigured by coating the silicon-containing particle (A), which is madeof silicon material and carbon material, with the electronic conductiveadditive (B), the preferable number average particle size ranges from0.1 to 30 μm. The particle having the number average particle size ofsmaller than 0.1 μm is difficult to be produced and hard to be handled.And, the particle having the number average particle size of greaterthan 30 μm is inferior in the conductivity in the active material andsuffers a deterioration in the cycle performance. The number averageparticle size of particles means the number average particle sizeobtained by means of a laser diffraction method. The number averageparticle size can be measured using, for example, SALD2000J (SHIMADZU.)

The particle size of the composite particle (C) in the present inventioncan be controlled by arranging the particle (A) so as to exhibit apredetermined particle size by means of grinding or screening with asieve, and by adjusting the amount of the electronic conductive additive(B) used for coating. The adjustment of coating amount can be made byadjusting, for example, the time required for CVD process.

The composite particle (C) described in the invention of claim 7 is asfollows: the composite particle (C) has a content of carbon, and whenthe composite particle (C) is measured at a temperature rising rate of10±2° C./min by thermogravimetry, weight loss appears at two stages in arange of temperature from 30 to 1000° C. The reason for this is thatusing such composite particle (C) makes it possible to obtain anon-aqueous electrolyte secondary battery which is excellent incharge/discharge cycle performance and has a high energy density.

In the above-described weight loss, the preferable temperature at whichweight loss starts in thermogravimetry of the composite particle (C) isnot higher than 600° C. at the first stage and is higher than 600° C. atthe second stage.

In addition, in the above-described weight loss, the preferableproportion of weight loss to the weight prior to the temperature rise inthermogravimetry of the composite particle (C) falls within the range of3 to 30 wt. % at the first stage and 5 to 65 wt. % at the second stage.

Carbon will differ in the temperature at which weight loss starts inthermogravimetry, depending on the different properties, so that thenature of carbon can be characterized according to the temperature atwhich weight loss starts. In addition, silicon hardly decreases inweight at a temperature range of 30 to 1000° C.

FIG. 1 shows the results of thermogravimetry of the composite particle(C) satisfying the above requirements. In the present invention, thetemperature at which weight loss starts at the first stage inthermogravimetry of the negative active material refers to thetemperature at point “a” in FIG. 1: at this point, the DTG curve,obtained by taking the first derivative of the region in a temperaturerange of 100° C. to 350° C. on the TG line, starts to deviate from theline “c” in FIG. 1, obtained by linearly approximating the DTG curve. Inaddition, the temperature at which weight loss at the first stage endsrefers to the temperature at point “b” in FIG. 1: the local minimumpoint on the DTG curve, or the point at the intersection of thefirst-stage weight loss with the second-stage weight loss on the DTGcurve, more specifically, the point at which, after the DTG curvestarted to exhibit the first-stage weight loss, it again changes theslope of the curve and starts to exhibit another weight loss. Inaddition, the temperature at which weight loss starts at the secondstage refers to the temperature at which weight loss newly starts,exceeding the temperature at which the first-stage weight loss ends.

In order to achieve excellent charge/discharge cycle performance in thenegative electrode, the preferable temperature at which weight lossstarts in thermogravimetry of the negative active material is not lowerthan 350° C. at the first stage and not higher than 800° C. at thesecond stage.

The first-stage weight loss means the amount of weight loss in thetemperature rising period from the temperature at which weight lossstarts, to the temperature at which weight loss ends at the first stage.Likewise, the second-stage weight loss means the amount of weight lossin the temperature rising period from the temperature at which weightloss starts to the temperature at which weight loss ends at the secondstage. In addition, weight loss in the present invention refers to theamount of weight loss to the weight of the negative active materialprior to the temperature rise.

In the silicon-carbon composite used as an active material in thepresent invention, the temperature at which weight loss starts and theamount of weight loss in thermogravimetry can be controlled in thefollowing manner.

Carbon powder is added to silicon powder, these powders are mixed andground in a ball mill, and then granulated bodies of silicon and carbonare prepared. The granulated particle thus prepared is put into astainless steel container, a nitrogen atmosphere is created entirely inthe stainless steel container while the container is agitated, theinternal temperature is then raised up to nearly 1000° C., subsequentlybenzene vapor is introduced in said stainless steel container, and CVDprocess is executed to coat the granulated body with carbon material.After that, the temperature is lowered down to the room temperatureunder nitrogen atmosphere, and a negative active material can beobtained. As silicon material other than silicon powder, it is alsopossible to use silicon oxides or their mixtures. In this case, with CVDtemperature being maintained lower than 1100° C., the temperature atwhich weight loss starts at the first stage can be kept not higher than600° C.

Various negative active materials, different in the temperature at whichweight loss starts and the amount of weight loss in thermogravimetry,can be prepared by changing the following factors: the average particlesize of silicon material; the average particle size, specific surfacearea, and average interplanar spacing d (002) of carbon powder; themixture ratio of silicon powder to carbon powder; the mixed grindingtime in a ball mill; and the type of organic constituent vapor to beintroduced in a container, temperature, and time for CVD process.

As a binder to be used in the negative electrode, a variety of materialsare usable accordingly without special limitation. For example, thefollowing materials or derivatives thereof can be used alone or incombination with two or more: styrene-butadiene rubber (SBR) orcarboxymethyl-cellulose (CMC), poly(vinylidene fluoride), carboxypoly(vinylidene fluoride), poly(tetrafluoroethylene),poly(tetrafluoroethylene-hexafluoroethylene),poly(tetrafluoroethylene-hexafluoropropylene), vinylidenefluoride-chlorotrifluoroethylene copolymer, poly(vinylidenefluoride-hexafluoropropylene), ethylene-propylene-diene copolymer,acrylonitrile-butadiene rubber, fluoro rubber, polyvinyl acetate,poly-methyl methacrylate, nitrocellulose, polyethylene, orpolypropylene.

As a solvent or solution to be used when the negative active materialand the binder are compounded, it is possible to use a solvent orsolution which is capable of dissolving or dispersing the binder; forexample, non-aqueous solvent or aqueous solution. The following can beincluded as an example of non-aqueous solvent: n-methyl-2-pyrrolidone,dimethyl formamide, dimethyl acetamide, methyl ethyl ketone,cyclohexanone, methyl acetate, methyl acrylate, diethyl triamine,n,n-dimethyl amino propyl amine, ethylene oxide, and tetrahydrofuran.

As a current collector of the negative electrode, usable materialsinclude iron, copper, stainless, or nickel. Concerning itsconfiguration, the following shapes can be used: sheet, plane, network,foam, sintered porosity, and expanded lattice. It is also possible touse the one which is configured by putting a hole in any shape in amaterial which has been formed into the above-listed shape.

As a positive active material to be used in the present invention, avariety of materials are usable accordingly without special limitation.For example, the transition metallic compounds such as manganese dioxideor vanadium pentoxide; the transition metallic chalcogenides such asiron sulfide or titanium sulfide; the composite oxides of suchtransition metal and lithium, Li_(x)MO_(2-δ) (composite oxides where Mrepresents Co, Ni, or Mn, 0.4≦X≦1.2, and 0≦δ≦0.5); or such compositeoxides which contain at least one element selected from the groupconsisting of Al, Mn, Fe, Ni, Co, Cr, Ti, and Zn, or nonmetallic elementsuch as P or B. It is also possible to use lithium-nickel compositeoxides, or the positive active materials represented byLi_(x)Ni_(p)M1_(q)M2_(r)O_(2-δ) (composite oxides where M1 and M2represent at least one element selected from the group consisting of Al,Mn, Fe, Ni, Co, Cr, Ti, and Zn, or nonmetallic element such as P or B;0.4≦X≦1.2, 0.8≦p+q+r≦1.2, and 0≦δ≦0.5.) Among them, capable of attaininghigh voltage and high energy density, and also superior in cycleperformance, lithium-cobalt composite oxides or lithium-cobalt-nickelcomposite oxides are preferred.

As a binder to be used in the positive electrode, a variety of materialsare usable accordingly without special limitation. For example, thefollowing materials or derivatives thereof can be used alone or incombination with two or more: poly(vinylidene fluoride), poly(vinylidenefluoride-hexafluoropropylene), poly(tetrafluoroethylene), fluorinatedpoly(vinylidene fluoride), ethylene-propylene-diene methylene linkage,styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluoro rubber,polyvinyl acetate, poly-methyl methacrylate, polyethylene, ornitrocellulose.

As an electronic conductive additive to be used in the positiveelectrode, a variety of materials are usable accordingly without speciallimitation. For example, Ni, Ti, Al, Fe or alloy of two or more of theseelements, or carbon material can be used. Among these, it is preferableto use carbon material. As some examples of carbon material, thefollowing amorphous carbon can be listed: natural graphite, artificialgraphite, vapor grown carbon fiber, acetylene black, ketjen black, andneedle coke.

As an organic solvent for the electrolyte solution to be used in thepresent invention, a variety of solvents are usable accordingly withoutspecial limitation. For example, ethers, ketones, lactones, nitriles,amines, amides, sulfur compounds, halogenated hydrocarbons, esters,carbonates, nitro compounds, phosphate ester compounds, and sulfolanehydrocarbons can be used. Among these, it is preferable to use ethers,ketones, esters, lactones, halogenated hydrocarbons, carbonates, orsulfolane hydrocarbons.

Furthermore, as some examples of these, there are tetrahydrofuran,2-methyl tetrahydrofuran, tetrahydropyran, 1,4-dioxan, anisole,monoglyme, 4-methyl-2-pentanone, methyl acetate, ethyl acetate, methylpropionate, ethyl propionate, 1,2-dichloroethane, γ-butyrolactone,γ-valerolactone, dimethoxyethane, diethoxyethane, methyl formate,dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropylcarbonate, methylpropyl carbonate, ethylene carbonate, propylenecarbonate, vinylene carbonate, butylene carbonate, dimethyl formamide,dimethyl sulfoxide, dimethyl formamide, sulfolane, 3-methyl sulfolane,trimethyl phosphate, triethyl phosphate, and phosphazene derivatives andmixed solvents thereof. Among these, ethylene carbonate, propylenecarbonate, γ-butyrolactone, dimethyl carbonate, methyl ethyl carbonate,and diethyl carbonate can be used alone or in combination with two ormore.

As a solute for the electrolyte to be used in the present invention, avariety of solutes are usable accordingly without special limitation.For example, the following can be used alone or in combination with twoor more: LiClO₄, LiBF₄, LiAsF₆, LiPF₆, LiCF(CF₃)₅, LiCF₂(CF₃)₄,LiCF₃(CF₃)₃, LiCF₄(CF₃)₂, LiCF₅(CF₃), LiCF₃(C₂F₅)₃, LiCF₃SO₃,LiN(CF₃SO₂)₂, LiN(C₂F₅SO₂)₂, LiN(C₂F₅CO)₂, LiI, LiAlCl₄, and LiBC₄O₈.Among them, the use of LiPF₆ is preferred. Moreover, it is preferablethat their lithium salt concentrations be 0.5 to 2.0 mol dm⁻³.

Furthermore, at least one material selected from the group consisting ofthe following may be contained in the electrolyte to be used: carbonatessuch as vinylene carbonate and butylene carbonate; benzenes such asbiphenyl and cyclohexylbenzen; sulfurs such as propane sultone;ethylenesulfide, hydrogen fluoride and triazole cyclic compounds;fluorine-containing esters; hydrogen fluoride complexes oftetraethylammonium fluoride or derivatives thereof; phosphazene and thederivatives; amido group-containing compounds; imino group-containingcompounds; or nitrogen-containing compounds. It is also possible to usethe electrolyte which contains at least one of the following: CO₂, NO₂,CO, or SO₂.

As a separator to be used in the present invention, a variety ofmaterials are usable accordingly without special limitation. There arefor example, woven fabric, nonwoven fabric, and synthetic-resinmicroporous membrane; among them, synthetic-resin microporous membraneis preferred. Concerning the material for the synthetic-resinmicroporous membrane, it is possible to use nylon, cellulose acetate,nitrocellulose, polysulfone, polyacrylonitrile; poly(vinylidenefluoride), and pollyolefins such as polyethylene, polypropylene, andpolybutene; among them, in the light of the thickness, strength, andresistance of membrane, the microporous membrane made of polyethylene orpolypropylene, or the polyolefin microporous membrane such aspolyethylene-polypropylene composite microporous membrane is preferred.It is also possible to use a separator which is configured by laminatingseveral sheets of microporous membrane different in material, weightaverage molecular weight, or porosity; or by adding an appropriateamount of additives of various kinds such as plasticizers, antioxidants,and flame retardants to such microporous membrane.

For the above described electrolyte, furthermore, an ion-conductingelectrolyte of a solid or gel state can be used either alone or incombination. In case of using it in combination, a non-aqueouselectrolyte secondary battery is configured with a positive electrode, anegative electrode, and a combination of a separator, an organic orinorganic solid electrolyte, and the above-described non-aqueouselectrolyte solution; or with a positive electrode, a negativeelectrode, and a combination of an organic or inorganic solidelectrolyte membrane, as a separator, and the above-describednon-aqueous electrolyte solution. It is also possible to use porouspolymer electrolyte membrane of a solid state for an ion-conductingelectrolyte. And for an ion-conducting electrolyte, the following can beused: polyethylene oxide, polypropylene oxide, polyacrylonitrile,polyethylene glycol, and derivatives thereof; and thio-licicon typifiedby LiI, Li₃N, Li_(1+X)M_(X)Ti_(2-X)(PO₄)₃ (where M=Al, Sc, Y, and La),Li_(0.5-3X)R_(0.5+X)TiO₃ (where R═La, Pr, Nd, and Sm), orLi_(4-X)Ge_(1-X)P_(X)S₄. It is also possible to use oxide glass such asLiI—Li₂O—B₂O₅ or Li₂O—SiO₂, or sulfide glass such as LiI—Li₂S—B₂S₃,LiI—Li₂S—SiS₂, or Li₂S—SiS₂—Li₃PO₄.

Furthermore, there is no special limitation on a form of battery; thepresent invention is applicable to non-aqueous electrolyte secondarybatteries of various forms including prismatic, elliptic, cylindrical,coin, button, and sheet type batteries.

Embodiment A Embodiment A1

Lithium cobalt oxide was used as a positive active material in thepreparation of a non-aqueous electrolyte secondary battery of aprismatic type. FIG. 2 shows the cross sectional configuration of anon-aqueous electrolyte secondary battery of a prismatic type. In FIG.2, the non-aqueous electrolyte secondary battery of a prismatic type isexpressed as 41, winding-type electrodes as 42, an positive electrode as43, a negative electrode as 44, a separator as 45, a battery case as 46,a battery cap as 47, a safety valve as 48, a positive terminal as 49,and a positive lead as 50.

The winding-type electrodes 42 is housed in the battery case 46, thebattery case 46 is equipped with the safety valve 48, and the batterycap 47 and the battery case 46 are sealed up by means of laser welding.The positive terminal 49 is connected with the positive electrode 43with the positive lead 50, and the negative electrode 44 is connected tothe inner wall of the battery case 46 in direct contact.

The positive electrode was prepared according to the following manner.90 wt. % of LiCoO₂ as an active material, 5 wt. % of acetylene black asa conductive material, and 5 wt. % of poly(vinylidene fluoride) as abinder were mixed together to form a positive composite, and thiscomposite was dispersed in N-methyl-2-pyrrolidone to make a positivepaste. The obtained positive paste was uniformly applied to an aluminumcurrent collector having a thickness of 20 μm, and after dried, theobtained material was compressed and molded by roll pressing to preparethe positive electrode.

The negative electrode was prepared according to the following manner.The surface of Si particle was coated with carbon material by means ofCVD method, and composite particle was prepared (which corresponds tothe composite particle in the present invention, and hereinafterreferred to as the composite particle (C)). The composite particle (C),which was configured so that the coating amount of the carbon materialwas 20 wt. %, was mixed with natural graphite (d002 of 0.3359 nm, andBET specific surface area of 7.4 cm²/g), as carbon material (whichcorresponds to the carbon material in the present invention, andhereinafter referred to as the carbon material (D)), in a weight ratioof 80:20 to prepare a negative active material. 90 wt. % of the obtainednegative active material and 10 wt. % of carboxy poly(vinylidenefluoride) as a binder were mixed together to form a negative composite,and this composite was dispersed in N-methyl-2-pyrrolidone to make anegative paste.

The above-obtained negative paste was uniformly applied to a copper foilhaving a thickness of 15 μm, and after dried at 100° C. for 5 hours,this material was compressed and molded by roll pressing to prepare thenegative electrode.

For the separator, a polyethylene microporous membrane having athickness of approximately 25 μm was used.

An electrolyte solution was prepared as follows: ethylene carbonate anddiethyl carbonate were mixed together in a volume ratio of 1:1, and then1.0 M of LiPF₆ was dissolved in the obtained mixture.

Embodiments A2 to A5, and Comparative Example A1

In these batteries, the following weight percentages were used as theamount of carbon coating in the composite particle (C): 0, 5, 40, 60,and 70 wt. %. Except for the above, the batteries have an identicalconfiguration to that of Embodiment A1.

These non-aqueous electrolyte secondary batteries were charged at aconstant current of 1 CmA and a constant voltage of 3.9 V at atemperature of 25° C. for 3 hours and made to reach a fully charged

state. Subsequently, they were discharged at a current of 1 CmA untilthe voltages dropped to 2.45 V. These steps were taken as one cycle andthe obtained discharge capacity was considered as the initial dischargecapacity. After that, under the same conditions as the above, a total of100 charge/discharge cycles were carried out, and the discharge capacityat the 1st cycle and a change in discharge capacity with an increase inthe number of cycle times (capacity retention ratio according to cycle)were determined. The results are shown in Table A1.

TABLE A1 Proportion of the Amount of carbon Proportion of the Capacitycomposite particle (C) coating in the carbon material (D) retentionratio Discharge in the negative active composite particle (C) in thenegative active according to capacity material (wt. %) (wt. %) material(wt. %) cycle (%) (mAh) EM A1 80 20 20 90 640 EM A2 80 5.0 20 89 650 EMA3 80 40 20 93 630 EM A4 80 60 20 94 590 CE A1 80 0 20 34 670 EM A5 8070 20 67 560

In Tables A1 to A4, EM in the first column refers to Embodiment and CErefers to Comparative Example; for example, EM A1 refers to EmbodimentA1 and CE A1 refers to Comparative Example A1.

Here, the capacity retention ratio according to cycle means thepercentage (%) obtained by dividing the discharge capacity at the100^(th) cycle by the one at the 1^(st) cycle.

As shown in the results of Embodiments A1 to A5 and Comparative ExampleA1, the batteries in which carbon coating was applied in the compositeparticle (C) are superior in the cycle performance, although the one inwhich the amount of carbon coating exceeds 70 wt. % shows adeterioration in the cycle performance; therefore, it is found that thepreferable amount of carbon coating is not greater than 60 wt. %. Inaddition, since initial discharge capacities decrease significantly whenthe amount of carbon coating exceeds 40 wt. %, it is also clear that themore preferable amount of carbon coating is not greater than 40 wt. %.

Embodiments A6 to A9

In these batteries, the following distances were used as the averageinterplanar spacing d (002) of the carbon to be used for coating in thecomposite particle (C): 0.3354 nm, 0.3482 nm, 0.3510 nm, and 0.370 nm.Except for the above, the batteries have an identical configuration tothat of Embodiment A1.

In the same manner as the above, the discharge capacity at the 1^(st)cycle and a change in discharge capacity with an increase in the numberof cycle times (capacity retention ratio according to cycle) weredetermined. The results are shown in Table A2.

TABLE A2 d(002) Capacity retention ratio Discharge capacity (nm)according to cycle (%) (mAh) EM A1 0.3359 90 640 EM A6 0.3354 89 650 EMA7 0.3482 81 638 EM A8 0.3510 74 635 EM A9 0.370 70 630

As shown in the results of the capacity retention ratios of EmbodimentsA1, and A6 to A9, it is preferable that the average interplanar spacingd (002) of the carbon for coating be not greater than 0.35 nm. It isbelieved that when the average interplanar spacing is greater than 0.35nm, the contact conductivity between the active material and between theactive material and the current collector decreases, so that the cycleperformance deteriorates.

Embodiments A10 to A14

In these batteries, the following areas were used as the BET specificsurface area of the composite particle (C): 1.0 m²/g, 6.3 m²/g, 10 m²/g,0.5 m²/g, and 11.0 m²/g. Except for the above, the batteries have anidentical configuration to that of Embodiment A1.

In the same manner as the above, the discharge capacity at the 1^(st)cycle and a change in discharge capacity with an increase in the numberof cycle times (capacity retention ratio according to cycle) weredetermined. The results are shown in Table A3.

TABLE A3 BET specific Capacity retention Discharge surface area ratioaccording capacity (m2/g) to cycle (%) (mAh) EM A1 7.4 90 640 EM A10 1.085 635 EM A11 6.3 81 638 EM A12 10.0 84 620 EM A13 0.5 62 630 EM A1411.0 79 590

These results reveal that when the BET specific surface area of thecomposite particle (C) falls within the range of 1.0 to 10.0 m²/g,satisfactory cycle performance is achieved. It is believed that when theBET specific surface area is less than 1.0 m²/g, the current density persurface area of the active material during charge/discharge becomeslarge; therefore, Li is deposited on the negative electrode andconsequently the cycle performance deteriorates. On the other hand, itis believed that when it exceeds 10 m²/g, the reaction area with theelectrolyte solution during charge becomes large and the decompositionof the electrolyte solution is made to proceed, so that the cycleperformance deteriorates. In addition, it is shown that when it exceeds10 m²/g, the discharge capacity deteriorates; thus, it is preferable toemploy the BET specific surface area of not larger than 10 m²/g.

Embodiments A15 to A17, and Comparative Example A2

In these batteries, the following weight ratios were used as the mixtureratio of the composite particle (C) to the carbon material (D):99.5:0.5, 60:40, 50:50, and 100:0. Except for the above, the batterieshave an identical configuration to that of Embodiment A1.

In the same manner as the above, the discharge capacity at the 1st cycleand a change in discharge capacity with an increase in the number ofcycle times (capacity retention ratio according to cycle) weredetermined. The results are shown in Table A4.

TABLE A4 Proportion of the Proportion of the Capacity composite particle(C) carbon material (D) retention ratio Discharge in the negative activein the negative active according to capacity material (wt. %) material(wt. %) cycle (%) (mAh) EM A1 80 20 90 640 EM A15 99.5 0.5 85 650 EM A1660 40 94 630 EM A17 50 50 95 580 CE A2 100 0 72 660

These results reveal that utilizing the carbon material (D) results inimprovement in the capacity retention ratio according to cycle. It isbelieved that the reason for this may be that the contact conductivitybetween the active material and between the active material and thecurrent collector deteriorates. Furthermore, it is shown that when theproportion of the carbon material (D) to the total weight of thecomposite particle (C) and the carbon material (D) lies in the range of0.5 to 40 wt. %, a battery having a large initial discharge capacity andsatisfactory cycle performance can be provided.

Embodiment B Embodiment B1

Lithium cobalt oxide was used as a positive active material in thepreparation of a non-aqueous electrolyte secondary battery of aprismatic type. FIG. 3 shows the cross sectional configuration of anon-aqueous electrolyte secondary battery of a prismatic type. In FIG.3, the non-aqueous electrolyte secondary battery of a prismatic type isexpressed as 21, winding-type electrodes as 22, an positive electrode as23, a negative electrode as 24, a separator as 25, a battery case as 26,a battery cap as 27, a safety valve as 28, a negative terminal as 29, apositive lead as 30, and a negative lead as 31.

The winding-type electrodes 22 is housed in the battery case 26, and thebattery cap 27 and the battery case 26 are sealed up by means of laserwelding. The battery cap 27 is equipped with the safety valve 28. Thenegative terminal 29 is connected with the negative electrode 24 withthe negative lead 31, and the positive electrode 23 is connected to theinner wall of the battery case 26 in direct contact and to the batterycap 27 with the positive lead 30.

A positive electrode plate was prepared according to the followingmanner. 90 wt. % of LiCoO₂ as an active material, 5 wt. % of acetyleneblack as a conductive material, and 5 wt. % of poly(vinylidene fluoride)as a binder were mixed together to form a positive composite, and thiscomposite was dispersed in N-methyl-2-pyrrolidone to make a positivepaste. The obtained positive paste was uniformly applied to an aluminumcurrent collector having a thickness of 20 μm, and after dried, thismaterial was compressed and molded by roll pressing to prepare thepositive electrode plate. The dimensions of the positive electrode platewere 160 μm in thickness, 18 mm in width, and 600 mm in length.

A negative active material was prepared according to the followingmanner. As silicon material, 400 g of carbon powder (average particlesize of 9 μm, specific surface area of 4 m²/g, and average interplanarspacing d002 of 0.3360 nm) were added to 500 g of silicon powder (purityof 99% and average particle size of 5 μm), these powders were mixed andground in a ball mill for 60 minutes, and then granulated bodies ofsilicon and carbon were prepared. 500 g of such granulated particle wasput into a stainless steel container, a nitrogen atmosphere was createdentirely in the stainless steel container while the container wasagitated, the internal temperature was then raised up to 1000° C.,subsequently benzene vapor was introduced in said stainless steelcontainer, and CVD process was executed for 120 minutes. After that, thetemperature was lowered down to the room temperature under nitrogenatmosphere, and the negative active material was obtained.

On the obtained negative active material, TG measurement was conducted,and in a temperature rise at a rate of 10±2° C./min, the following twostages of weight loss were observed: at the first stage, the temperatureat which weight loss started (hereinafter referred to as T1) was 570° C.and the amount of weight loss (hereinafter referred to as W1) was 15 wt.%; and at the second stage, the temperature at which weight loss started(hereinafter referred as to T2) was 700° C. and the amount of weightloss (hereinafter referred as to W2) was 30 wt. %.

A negative electrode plate was prepared according to the followingmanner. 90 wt. % of the above-described negative active material and 10wt. % of carboxy poly(vinylidene fluoride) as a binder were mixedtogether to form a negative composite, the obtained composite wasdispersed in N-methyl-2-pyrrolidone to make a negative paste, theobtained paste was uniformly applied to a copper foil having a thicknessof 15 μm, and after dried at 100° C. for 5 hours, this material wascompressed and molded by roll pressing to prepare the negativeelectrode. The dimensions of the negative electrode plate were 180 μm inthickness, 19 mm in width, and 630 mm in length.

For the separator, a polyethylene microporous membrane having athickness of 20 μm was used. An electrolyte solution was prepared asfollows: ethylene carbonate and diethyl carbonate were mixed together ina volume ratio of 1:1, and 1.0 M of LiPF₆ was dissolved in the obtainedmixture.

And, a winding-type power generating element was configured as follows:the positive and negative electrode plates were overlapped each otherwith the separator therebetween, and spirally wound in an elliptic shapearound a polyethylene core as a center. This winding-type powergenerating element was then housed in the iron battery case of aprismatic type, the battery case was filled with the electrolytesolution, the filling port was sealed, and thus the battery wasprepared. The dimensions of the battery were 47 mm in length, 23 mm inwidth, and 8 mm in thickness, and the rated capacity was 600 mAh. Thisbattery was termed Battery A.

This non-aqueous electrolyte secondary battery was charged at a constantcurrent of 600 mA at a temperature of 25° C., at first until the voltagereached 4.2 V and, when reached, at a constant voltage of 4.2 V, for atotal of 3 hours, and made to reach a fully charged state. Subsequently,the battery was discharged at a constant current of 600 mA until thevoltage dropped to 2.45 V. These steps were taken as one cycle and theobtained discharge capacity was considered as the initial dischargecapacity. After that, under the same conditions as the above, a total of100 charge/discharge cycles were carried out, and the discharge capacityat the 1^(st) cycle (initial discharge capacity), the thickness ofbattery at the 1^(st) charge/discharge cycle, and a change in dischargecapacity with an increase in the number of charge/discharge cycles weredetermined. Here, the percentage (%) of the discharge capacity at the100^(th) cycle to the one at the 1^(st) cycle refers to “capacityretention ratio.”

Except for using the negative active materials which differ in thenumber of the stages at which weight loss appeared, the temperature atwhich weight loss started, and the amount of weight loss in the TGmeasurement conducted at a temperature rising rate of 10±2° C./rain, thebatteries listed in Table B2 have an identical configuration to that ofEmbodiment B1. The producing conditions used for each battery are listedin Table B3.

The carbon material for each Embodiment and Comparative Example wasprepared in the following manner. A given amount of carbon powderfeeding, listed in Table B1, was added to 500 g of silicon powder; thesepowders were milled in a ball mill for a given period of time, listed inTable B1, to prepare granulated bodies; 500 g of such granulatedparticle was then put into a stainless steel container; the internaltemperature was raised up to a given temperature for CVD process, listedin Table B1; benzene vapor was introduced; and CVD process was performedfor a given period of time, listed in Table B1.

TABLE B1 Temperature Time for Time for Amount of Bat- for CVD CVDprocess ball milling feeding tery process ° C. min. min. g EM B1 A 1000120 60 400 EM B2 B 800 120 60 400 EM B3 C 1050 120 60 400 EM B4 D 1000120 120 400 EM B5 E 1000 120 40 400 EM B6 F 780 120 60 400 EM B7 G 1000120 30 400 EM B8 H 1000 40 60 400 EM B9 I 1000 200 60 400 EM B10 J 1000120 60 130 EM B11 K 1000 120 60 800 EM B12 L 1000 120 60 400 CM B1 M — —— — CE B2 N 1000 120 — — CE B3 O 1200 120 — — EM B13 P 1100 120 60 400EM B14 Q 1000 120 140 400 EM B15 R 1000 8 60 400 EM B16 S 1000 320 60400 EM B17 T 1000 120 60 40 EM B18 U 1000 120 60 930In Tables B1 to B3, EM in the first column refers to Embodiment and CErefers to Comparative Example; for example, EM B1 refers to EmbodimentB1 and CE B1 refers to Comparative Example B1.

TABLE B2 Temperature at Number of stages which weight Amount of at whichweight loss started weight loss loss appeared ° C. % Battery in TGmeasurement T1 T2 W1 W2 EM B1 A 2 570 700 15 30 EM B2 B 2 370 700 15 30EM B3 C 2 590 700 15 30 EM B4 D 2 570 620 15 30 EM B5 E 2 570 780 15 30EM B6 F 2 340 700 15 30 EM B7 G 2 570 810 15 30 EM B8 H 2 570 700 5 30EM B9 I 2 570 700 25 30 EM B10 J 2 570 700 15 10 EM B11 K 2 570 700 1560 EM B12 L 2 570 700 15 30 CE B1 M 0 — — — — CE B2 N 1 570 — 15 — CE B3O 1 650 — 15 — EM B13 P 2 620 700 15 30 EM B14 Q 2 570 580 15 30 EM B15R 2 570 700 1 30 EM B16 S 2 570 700 40 30 EM B17 T 2 570 700 15  3 EMB18 U 2 570 700 15 70

TABLE B3 Initial discharge Battery thickness Capacity Bat- capacityduring charge retention ratio tery mAh mm % EM B1 A 650 6.10 90 EM B2 B650 6.15 89 EM B3 C 650 6.10 88 EM B4 D 650 6.10 86 EM B5 E 650 6.15 90EM B6 F 640 6.20 68 EM B7 G 640 6.20 72 EM B8 H 660 6.15 85 EM B9 I 6456.10 90 EM B10 J 665 6.10 86 EM B11 K 635 6.10 91 EM B12 L 628 6.10 96CE B1 M 630 6.50 20 CE B2 N 630 6.25 40 CE B3 O 670 6.30 50 EM B13 P 6506.30 63 EM B14 Q 640 6.30 61 EM B15 R 660 6.30 52 EM B16 S 625 6.10 56EM B17 T 665 6.30 38 EM B18 U 605 6.10 53

The evaluation results for these batteries are shown in Table B3.

These results reveal the following findings. In the batteries having thenegative active material which exhibits two-stage weight loss, thethickness of the batteries during charge is small and thecharge/discharge cycle performance is satisfactory. On the other hand,in the battery having the negative active material which exhibits noweight loss, the thickness of the battery during charge is large and thecharge/discharge cycle performance is unsatisfactory. In addition, inthe batteries having the negative active material which exhibitsone-stage weight loss, the charge/discharge cycle performance isunsatisfactory. Moreover, those having the negative active material inwhich T1 is not higher than 600° C. and T2 is not lower than 600° C.show extremely excellent charge/discharge cycle performance.

Furthermore, in the batteries having the negative active material inwhich W1 and W2 fall within the ranges of 3 to 30 wt. % and 5 to 65 wt.%, respectively, to the weight prior to the temperature rise in TGmeasurement, it is found that the swelling of the batteries is notsignificant and extremely excellent charge/discharge cycle performanceis exhibited. In addition, in Battery L having the negative activematerial which was prepared using a mixture of carbon and silicon-carboncomposite, although the initial discharge capacity is a little inferiorto that of Battery A, the capacity retention ratio stands at 96% andtherefore further improvement in charge/discharge cycle performance wasable to be confirmed.

Embodiment C

FIGS. 4 to 7 show schematic views of the composite particle described inclaim 6. FIG. 4 is a schematic view illustrating the composite particle10, which is composed of the particle 11 consisting of Si, the particle12 consisting of SiO_(x) (where 0<X≦2), and the carbon material A13.

The above composite particle 10 can be obtained by milling the particle11 consisting of Si, the particle 12 consisting of SiO_(x), and thecarbon material A13 with the use of a milling machine. Such a millingprocess can be carried out in the air; however, an inert atmosphere suchas argon or nitrogen is preferred. There are following types of millingprocess: ball mill, vibration mill, satellite ball mill, tube mill, jetmill, rod mill, hammer mill, roller mill, disc mill, attritor mill,planetary ball mill, and impact mill. It is also possible to usemechanical alloying method. The applicable range of milling temperatureis from 10° C. to 300° C.; and that of milling time is from 30 secondsto 48 hours.

FIG. 5 is a schematic view illustrating the composite particle, which isconfigured by coating the surface of the above-described compositeparticle 10 with the carbon material B14. FIG. 6 is a schematic viewillustrating the composite particle 16, which is composed of theparticle 15 containing Si and SiO_(x) (where 0<X≦2) and the carbonmaterial A13. Such composite particle 16 can be obtained according tothe preparation procedures identical to those of the composite particle10, by using the particle 15 containing Si and SiO_(x) and the carbonmaterial A13. FIG. 7 is a schematic view illustrating the compositeparticle, which is configured by coating the surface of theabove-described composite particle 16 with the carbon material B14.

In order to coat the surface of the composite particle 10 or 16 with thecarbon material B14, the following methods can be used: coating thesurface of the composite particle 10 or 16 with an organic compound andthen performing calcination; or utilizing chemical vapor deposition(CVD) technique.

In CVD method, it is possible to use organic compounds such as methane,acetylene, benzene, toluene, etc. as a reaction gas. The applicablereaction temperature and time, respectively, range from 700° C. to 1300°C. and from 30 seconds to 72 hours. Using CVD method, coating treatmentwith carbon material can be implemented at a lower reaction temperature,in comparison with the method of calcinating an organic compound on thesurface. Therefore, CVD method is preferred in that the coatingtreatment can be performed at a temperature not higher than therespective melting points of the particle 11 consisting of Si, theparticle 12 consisting of SiO_(x), and the particle 15 containing Si andSiO_(x).

By performing Raman spectroscopic analysis, it is possible to determinewhether or not the surface of the composite particle 10 is coated withthe carbon material B14. Since the surface area of a sample is analyzedby Raman spectroscopic analysis, if the surface of the compositeparticle 10 is entirely coated with the carbon material B14, R value(intensity ratio of a peak intensity of 1360 cm⁻¹ to a peak intensity of1580 cm⁻¹), which indicates the crystalline quality of the carbonmaterial B14 on the surface, should stand at a constant value wherevermeasurement is taken on the particle of the negative active material.For conducting Raman spectroscopic analysis, it is possible to use, forexample, a spectrometer T64000 (JOBIN YVON).

Regarding the particle consisting of Si, the particle consisting ofSiO_(x) (where 0<X≦2), or the particle containing Si and SiOx (where0<X≦2), the following can also be used: the particles which have beenwashed with such acid as fluorinated acid or sulfuric acid, or theparticles which have been reduced with hydrogen.

The proportions of the carbon material A13 and the carbon material B14to the entire negative active material can be determined by means ofthermogravimetry. For example, in thermogravimetry at a temperaturerising rate of 10±2° C./min, the carbon material A13 and the carbonmaterial B14 are observed to exhibit weight loss in a temperature rangeof 30° C. to 1000° C. In the vicinity of 580° C., the carbon materialB14 of relatively low crystalline on the surface of the compositeparticle 10 is observed to exhibit weight loss, and next in the vicinityof 610° C., the carbon material A13 which was milled together with theparticle 11 consisting of Si, the particle 12 consisting of SiO_(x), andthe particle 15 containing Si and SiO_(x), is observed to exhibit weightloss. The particle 11 consisting of Si, the particle 12 consisting ofSiO_(x), and the particle 15 containing Si and SiO_(x) are observed toexhibit weight loss in a range of around 1500° C. to 2000° C. Based onthese results, the weight ratio of each material can be determined.

As a device for such thermogravimetry, it is possible to use, forexample, SSC/5200 (Seiko Instruments Inc.). The specific surface area ofthe negative active material can be determined by low-temperature gasadsorption technique, according to dynamic constant pressure method at arange of pressure measurement from 0 to 126.6 KPa, using, for example, amicromeritics analyzer GEMINI2370 (SHIMADZU) with the use of liquidnitrogen, and analyzed by means of BET method. And as data processingsoftware, GEMINI-PC1 can be used.

Embodiment C1

As a negative active material, composite particle was prepared bytreating 30 parts by weight of Si, 30 parts by weight of SiO₂, and 40parts by weight of artificial graphite under nitrogen atmosphere by ballmilling at 25° C. for 30 minutes.

95 wt. % of the above-obtained negative active material, 3 wt. % of SBR,and 2 wt. % of CMC were mixed in water to prepare a negative paste. Theobtained negative paste was applied to a copper foil having a thicknessof 150° C. so that the weight of the coating could be 1.15 mg/cm² andthe quantity of the negative active material to be housed in the batterycould be 2 g, and then dried at 150° C. to evaporate water. This processwas performed on both sides of the copper foil, which then compressedand molded by roll pressing. Thus, a negative electrode plate both sidesof which were coated with the negative composite layer was prepared.

90 wt. % of lithium cobalt oxide as a positive active material, 5 wt. %of acetylene black as a conductive material, and 5 wt. % of PVDF as abinder were dispersed in NMP to make a positive paste. The

obtained positive paste was applied to an aluminum foil having athickness of 20 μm so that the weight of the coating could be 2.5 mg/cm²and the quantity of the positive active material to be housed in thebattery could be 5.3 g, and then dried at 150° C. to evaporate NMP. Theabove-described process was performed on both sides of the aluminumfoil, which then compressed and molded by roll pressing. Thus, apositive electrode plate both sides of which were coated with thepositive composite layer was prepared.

A winding-type power generating element was made by overlapping andwinding the positive and negative electrode plates thus prepared with apolyethylene separator, with continuous porosity having a thickness of20 μm and a porosity of 40%, being placed between them. Thiswinding-type power generating element was housed in the case having 48mm in height, 30 mm in width, and 4.2 mm in thickness, the case was thenfilled with a non-aqueous electrolyte solution, and thus a non-aqueouselectrolyte secondary battery of a prismatic type was prepared. The usednon-aqueous electrolyte solution was prepared as follows: ethylenecarbonate (EC) and diethyl carbonate (DEC) were mixed together in avolume ratio of 1:1, and 1 mol/l of LiPF₆ was dissolved in the mixedsolvent thus prepared.

Embodiment C2

In Embodiment C2, a negative active material was prepared as follows:composite particle was prepared by treating 20 parts by weight of Si, 20parts by weight of SiO₂, and 40 parts by weight of artificial graphiteunder nitrogen atmosphere by ball milling at 25° C. for 30 minutes, andafter that, by means of the method (CVD) of thermally decomposingmethane at 900° C., the surface of the composite particle was coatedwith carbon material. Except for using the negative active material thusprepared, the non-aqueous electrolyte secondary battery has an identicalconfiguration to that of Embodiment C1.

Embodiment C3

In Embodiment C3, SiO was used in stead of SiO₂. Except for the above,the non-aqueous electrolyte secondary battery has an identicalconfiguration to that of Embodiment C2

Comparative Examples C1 to C4

In Comparative Examples C1 to C4, those listed in Table C1 wereemployed. Except for the above, the non-aqueous electrolyte secondarybatteries have an identical configuration to that of Embodiment C2.

<Measurement>

(Raman Spectroscopic Analysis)

On each negative active material prepared as above, Raman spectroscopicanalysis was conducted according to the above-described manner todetermine an R value. The R value was found to be approximately 0.8 inany measurement point on the particle of the negative active material.This R value will stand at 0 when the sample is highly crystalline, andas the crystalline quality becomes lower, the value will become larger.Because of the value being approximately 0.8, this particle wasconfirmed to be uniformly coated with the carbon material of relativelylow crystalline which was deposited by means of CVD method.

(Thermogravimetry)

On each negative active material prepared as above, thermogravimetry wasemployed according to the above-described manner, and the weight ratioof each material was determined.

(XRD)

On each negative active material prepared as above, X-ray diffractionwas performed according to the above-described manner, and the averageinterplanar spacing d(002) of the carbon material was determined fromthe diffraction angle (2θ) in the X-ray diffraction pattern with CuKαradiation.

(BET Specific Surface Area)

For each negative active material prepared as above, BET specificsurface area was determined according to the above-described manner.

(Charge/Discharge Performance)

Each non-aqueous electrolyte secondary battery prepared as above wascharged at a current of 1 CmA at a temperature of 25° C. until thevoltage reached 4.2 V, subsequently charged at a constant voltage of 4.2V for 2 hours, and then discharged at a current of 1 CmA until thevoltage dropped to 2.0 V. These steps were taken as one cycle and thecharge/discharge test was repeated 500 cycles. The ratio (expressed inpercentage) of the discharge capacity at the 500^(th) cycle to the oneat the 1^(st) cycle referred to the capacity retention ratio accordingto cycle.

<Results>

The results of measurement were summarized in Table C1.

In Embodiments C1 to C3, the capacity retention ratios are higher thanthat of Comparative Example C1, where SiO_(x) is not contained, and thedischarge capacities are larger than that of Comparative Example C2,where Si is not contained. In addition, the capacity retention ratiosare higher than that of Comparative Example C3, where carbon material isnot contained in the composite particle, and the discharge capacitiesare larger than that of Comparative Example C4, where Si and SiO_(x) arenot contained.

Embodiments C2 and C3, where the particle (A) is coated with carbon, aresuperior in the capacity retention ratios, compared to Embodiment C1.

Embodiments C4 to C8

In Embodiments C4 to C8, as the proportions of the weight of Si to thetotal weight of Si and SiO₂, those listed in Table C2 were used. Exceptfor the above, the non-aqueous electrolyte secondary batteries have anidentical configuration to that of Embodiment C2. In addition, variousmeasurement results regarding these embodiments were summarized in TableC2.

The batteries where the proportions of the weight of the particleconsisting of Si to the total weight of the particle consisting of Siand the particle consisting of SiO_(x) fall within the range of 20 wt. %to 80 wt. % have larger discharge capacities compared to the batterywhere the proportion of the weight of the particle consisting of Sistands at 10 wt. %.

Embodiments C9 to C14

In Embodiments C9 to C14, as the proportions of the additive amount ofthe artificial graphite which is mixed together with Si and SiO₂, thoselisted in Table C3 were used. Except for the above, the non-aqueouselectrolyte secondary batteries have an identical configuration to thatof Embodiment C2. Various measurement results regarding theseembodiments were summarized in Table C3.

The batteries where the proportions of the artificial graphite to theentire negative active material fall within the range of 3 wt. % to 60wt. % have higher capacity retention ratios compared to the batterywhere the proportion of the artificial graphite stands at 1 wt. %. Onthe other hand, those batteries have larger discharge capacitiescompared to the battery where the proportion of the artificial graphitestands at 70 wt. %.

The batteries where the proportions of the total carbon material to theentire negative active material fall within the range of 30 wt. % to 80wt. % have higher capacity retention ratios compared to the batterieswhere the proportions of the total carbon material stand at 21 wt. % and23 wt. %, respectively. In addition, the former batteries have largerdischarge capacities and higher capacity retention ratios compared tothe battery where the proportion of the total carbon material stands at90 wt. %.

Embodiments C15 to C17

As the carbon material which is mixed together with Si and SiO₂, naturalgraphite, acetylene black, and vapor grown-carbon fiber were used inEmbodiments C15, C16, and C17, respectively, instead of artificialgraphite. Except for the above, the non-aqueous electrolyte secondarybatteries have an identical configuration to that of Embodiment C2.Various measurement results regarding these embodiments as well as thoseof Embodiment C2 were summarized in Table C4.

Embodiments C2, C15, and C17, where the average interplanar spacingd(002) fall within the range of 0.3354 nm to 0.35 nm, have largerdischarge capacities and higher capacity retention ratios compared toEmbodiment C16, where d(002) is 0.37 nm.

Embodiments C18 to 020

In Embodiments C18 to C20, as the amounts of the carbon with which thesurface of the composite particle was coated, those listed in Table C5were employed to prepare negative active materials. Those values wereobtained by appropriately varying the reaction conditions in the coatingtreatment with carbon material by means of CVD method. Except for theabove, the non-aqueous electrolyte secondary batteries have an identicalconfiguration to that of Embodiment C2.

Various measurement results regarding these embodiments as well as thoseof Embodiment C2 were summarized in Table C5.

Embodiments C2, C18, and C19, where the proportions of the carbonmaterial on the surface of the composite particle to the entire negativeactive material fall within the range of 0.5 wt. % to 40 wt. %, havelarger discharge capacities and higher capacity retention ratioscompared to Embodiment C20, where the proportion of the carbon materialis 50 wt. %.

Embodiments C21 to C23

In Embodiments C21 to C23, the negative active materials were preparedemploying the BET specific surface areas listed in Table C6. Thosesurface areas were obtained by using the Si, SiO₂, and artificialgraphite which have predetermined specific surface areas. Except for theabove, the non-aqueous electrolyte secondary batteries have an identicalconfiguration to that of Embodiment C2. Various measurement resultsregarding these embodiments as well as those of Embodiment C2 weresummarized in Table C6.

Embodiments C2, C21, and C22, where the BET specific surface areas arenot greater than 10.0 m²/g, have larger discharge capacities and highercapacity retention ratios compared to Embodiment C23, where the BETspecific surface area is 20.0 m²/g.

Embodiment C24

In Embodiment C24, a negative active material was prepared as follows:composite particle was prepared by treating 60 parts by weight of theparticle, where Si and SiO₂ are contained in a weight ratio of 1:1, and40 parts by weight of artificial graphite under nitrogen atmosphere byball milling at 25° C. for 30 minutes. Except for using the negativeactive material thus prepared, the non-aqueous electrolyte secondarybattery has an identical configuration to that of Embodiment C1.

Embodiment C25

In Embodiment C25, a negative active material was prepared as follows:composite particle was prepared by treating 40 parts by weight of theparticle, where Si and SiO₂ are contained in a weight ratio of 1:1, and40 parts by weight of artificial graphite under nitrogen atmosphere byball milling at 25° C. for 30 minutes; and after that, by means of themethod (CVD) of thermally decomposing methane at 900° C., the surface

of such composite particle was coated with carbon material. Except forusing the negative active material thus prepared, the non-aqueouselectrolyte secondary battery has an identical configuration to that ofEmbodiment C24.

Embodiment C26

In Embodiment C26, SiO was used in stead of SiO₂. Except for the above,the non-aqueous electrolyte secondary battery has an identicalconfiguration to that of Embodiment C25.

For the negative active materials in Embodiments C24 to C26, measurementdata of Raman spectroscopic analysis, thermogravimetry, XRD, and BETspecific surface area were taken according to the same manner asdescribed in Embodiment C1. In addition, for the non-aqueous electrolytesecondary batteries in Embodiments C24 to C26, charge/dischargeperformance was determined according to the same manner as described inEmbodiment C1. The results are shown in Table C7, in which data fromComparative Examples C1 to C4 shown in Table C1 was also included forcomparison.

<Results>

In Embodiments C24 to C26, the capacity retention ratios are higher thanthat of Comparative Example C1, where SiO_(x) is not contained; and thedischarge capacities are larger than that of Comparative Example C2,where Si is not contained. In addition, the capacity retention ratiosare higher than that of Comparative Example C3, where carbon material isnot contained in the composite particle; and the discharge capacitiesare larger than that of Comparative Example C4, where Si and SiO_(x) arenot contained.

Embodiments C25 and C26, where the composite particle is coated with thecarbon material, are superior in the capacity retention ratios comparedto Embodiment C24.

Embodiments C27 to C31

In Embodiments C27 to C31, as the proportions of Si in the particlecontaining Si and SiO₂, those listed in Table C8 were used. Except forthe above, the non-aqueous electrolyte secondary batteries have anidentical configuration to that of Embodiment C25.

Various measurement results regarding these embodiments as well as thoseof Embodiment C25 and Comparative Examples C1 and C2 were summarized inTable C8.

Embodiments C25, C28, and C31, where the proportions of Si in theparticle containing Si and SiO₂ fall within the range of 20 wt. % to 80wt. %, have larger discharge capacities compared to Embodiment C27,where the proportion of Si stands at 10 wt. %.

Embodiments C32 to C37

In Embodiments C32 to C37, as the proportions of the additive amount ofthe artificial graphite which is mixed together with the particlecontaining Si and SiO₂, those listed in Table C9 were used. Except forthe above, the non-aqueous electrolyte secondary batteries have anidentical configuration to that of Embodiment C25.

Various measurement results regarding these embodiments were summarizedin Table C9.

Embodiments C33 to C36, where the proportions of the artificial graphiteto the entire negative active material fall within the range of 3 wt. %to 60 wt. %, have higher capacity retention ratios compared toEmbodiment C32, where the proportion of the artificial graphite standsat 1 wt. %. On the other hand, Embodiments C33 to C36 have largerdischarge capacities compared to Embodiment C37, where the proportion ofthe artificial graphite stands at 70 wt. %.

In addition, Embodiments C34 to C36, where the proportions of the totalcarbon material to the entire negative active material fall within therange of 30 wt. % to 80 wt. %, have higher capacity retention ratioscompared to Embodiments C32 and C33, where the proportions of the totalcarbon material stand at 21 wt. % and 23 wt. %, respectively.Embodiments C34 to C36 have larger discharge capacities and highercapacity retention ratios compared to Embodiment C37, where theproportion of the total carbon material stands at 90 wt. %.

TABLE C1 Specific Capacity Particle (A) Coating surface Dischargeretention Si SiO₂ SiO Carbon Carbon d(002) area capacity ratio (wt. %)(wt. %) (wt. %) (wt. %) (wt. %) (nm) (m²/g) (mAh) (%) EM C1 30 30 0 40 00.34 5 815 71 EM C2 20 20 0 40 20 0.34 5 774 82 EM C3 20 0 20 40 20 0.345 780 76 CE C1 40 0 0 40 20 0.34 5 812 49 CE C2 0 40 0 40 20 0.34 5 52059 CE C3 40 40 0 0 20 0.345 5 820 43 CE C4 0 0 0 80 20 0.34 5 601 72In Tables C1 to C9, EM in the first column refers to Embodiment and CErefers to Comparative Example; for example, EM C1 refers to EmbodimentC1 and CE C1 refers to Comparative Example C1.

TABLE C2 Proportion to Proportion to the entire the sum of Si negativeactive material Specific Capacity and SiO₂ Particle (A) Coating surfaceDischarge retention Si SiO₂ Si SiO₂ Carbon Carbon d(002) area capacityratio (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (nm) (m²/g) (mAh)(%) CE C2 0 100 0 40 40 20 0.34 5 520 59 EM C4 10 90 4 36 40 20 0.34 5672 61 EM C5 20 80 8 32 40 20 0.34 5 740 73 EM C6 40 60 16 24 40 20 0.345 768 76 EM C2 50 50 20 20 40 20 0.34 5 774 82 EM C7 60 40 24 16 40 200.34 5 782 77 EM C8 80 20 32 8 40 20 0.34 5 798 72 CE C1 100 0 40 0 4020 0.34 5 812 49

TABLE C3 Specific Capacity Particle (A) Coating surface Dischargeretention Si SiO₂ Carbon Carbon d(002) area capacity ratio (wt. %) (wt.%) (wt. %) (wt. %) (nm) (m²/g) (mAh) (%) EM C9 39.5 39.5 1 20 0.34 5 80752 EM C10 38.5 38.5 3 20 0.34 5 802 69 EM C11 30 30 20 20 0.34 5 805 79EM C12 20 20 40 20 0.34 5 774 82 EM C13 10 10 60 20 0.34 5 772 78 EM C145 5 70 20 0.34 5 682 68

TABLE C4 Specific Capacity Particle (A) Coating surface Dischargeretention Si SiO₂ Carbon Carbon d(002) area capacity ratio (wt. %) (wt.%) (wt. %) (wt. %) (nm) (m²/g) (mAh) (%) EM C15 20 20 40 20 0.3354 5 78073 EM C2 20 20 40 20 0.34 5 774 82 EM C16 20 20 40 20 0.37 5 709 65 EMC17 20 20 40 20 0.35 5 789 81

TABLE C5 Specific Capacity Particle (A) Coating surface Dischargeretention Si SiO₂ Carbon Carbon d(002) area capacity ratio (wt. %) (wt.%) (wt. %) (wt. %) (nm) (m²/g) (mAh) (%) EM C18 29.75 29.75 40 0.5 0.345 811 80 EM C2 20 20 40 20 0.34 5 774 82 EM C19 10 10 40 40 0.34 5 75283 EM C20 5 5 40 50 0.34 5 702 70

TABLE C6 Specific Capacity Particle (A) Coating surface Dischargeretention Si SiO₂ Carbon Carbon d(002) area capacity ratio (wt. %) (wt.%) (wt. %) (wt. %) (nm) (m²/g) (mAh) (%) EM C21 20 20 40 20 0.34 1 78279 EM C2 20 20 40 20 0.34 5 774 82 EM C22 20 20 40 20 0.34 10 776 70 EMC23 20 20 40 20 0.34 20 721 61

TABLE C7 Capacity Particle (A) Coating Specific Discharge retention SiSiO₂ SiO Carbon Carbon d(002) surface capacity ratio (wt. %) (wt. %)(wt. %) (wt. %) (wt. %) (nm) area (m²/g) (mAh) (%) EM C24 30 30 0 40 00.34 5 819 79 EM C25 20 20 0 40 20 0.34 5 782 84 EM C26 20 0 20 40 200.34 5 795 83 CE C1 40 0 0 40 20 0.34 5 812 49 CE C2 0 40 0 40 20 0.34 5520 59 CE C3 40 40 0 0 20 0.345 5 820 43 CE C4 0 0 0 80 20 0.34 5 601 72

TABLE C8 Proportion to Proportion to the entire the sum of Si negativeactive material Specific Capacity and SiO₂ Particle (A) Coating surfaceDischarge retention Si SiO₂ Si SiO₂ Carbon Carbon d(002) area capacityratio (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (nm) (m²/g) (mAh)(%) CE C2 0 100 0 40 40 20 0.34 5 520 69 EM C27 10 90 4 36 40 20 0.34 5675 75 EM C28 20 80 8 32 40 20 0.34 5 749 79 EM C29 40 60 16 24 40 200.34 5 773 83 EM C25 50 50 20 20 40 20 0.34 5 782 84 EM C30 60 40 24 1640 20 0.34 5 795 81 EM C31 80 20 32 8 40 20 0.34 5 803 77 CE C1 100 0 400 40 20 0.34 5 812 49

TABLE C9 Capacity Particle (A) Coating Specific Discharge retention SiSiO₂ Carbon Carbon d(002) surface capacity ratio (wt. %) (wt. %) (wt. %)(wt. %) (nm) area(m²/g) (mAh) (%) EM C32 39.5 39.5 1 20 0.34 5 815 67 EMC33 38.5 38.5 3 20 0.34 5 807 76 EM C34 30 30 20 20 0.34 5 802 79 EM C3520 20 40 20 0.34 5 782 84 EM C36 10 10 60 20 0.34 5 776 81 EM C37 5 5 7020 0.34 5 701 78

Embodiment D Embodiment D1

To the particle consisting of both microcrystalline Si phase andamorphous SiO_(x) phase (hereinafter such particle is referred to as theparticle (S)), X-ray diffraction technique with the use of CuKαradiation was utilized. As a result, on the particle (S), diffractionpeaks appeared in a range of diffraction angle (2θ) from 46° to 49° andthe half width of the main diffraction peak appearing in said range wassmaller than 3° (2θ).

The surface of such particle (S) was coated with carbon using the method(CVD) of thermally decomposing benzene gas under argon atmosphere at1000° C., so that the composite particle (C) was prepared. The amount ofthe carbon coating was determined to be 20 wt. % to the total amount ofthe particle (S) and the carbon as coating material. The number averageparticle size of the composite particle (C) was 10 μm. The numberaverage particle size of particle is defined as a number average whichcan be obtained by laser diffraction technique.

With the use of such composite particle (C), a non-aqueous electrolytesecondary battery was produced according to the following manner. First,10 wt. % of the composite particle (C) and, as the carbon material (D),40 wt. % of meso carbon micro beads (MCMB), 30 wt. % of natural graphiteand 20.0 wt. % of artificial graphite were mixed together to prepare anegative active material. An illustration of this type of negativeactive material can be seen in FIG. 8, which shows a mixture of carbonmaterial (D) 31 and composite particles (C) 60.

97 wt. % of the above-obtained negative active material, 2 wt. % ofstyrene-butadiene rubber (SBR), and 1 wt. % of carboxymethyl-cellulose(CMC) were mixed in water to prepare a paste. The obtained paste wasapplied to a copper foil having a thickness of 15 μm so that the weightof the coating could be 1.15 mg/cm² and the quantity of the negativeactive material to be housed in the battery could be 2 g, and then driedat 150° C. to evaporate water. This process was performed on both sidesof the copper foil, which then compressed and molded by roll pressing.Thus, a negative electrode plate, or the copper foil both sides of whichwere coated with the negative composite layer, was prepared.

Next, 90 wt. % of lithium cobalt oxide, 5 wt. % of acetylene black, and5 wt. % of poly(vinylidene fluoride) (PVdF) were dispersed in NMP tomake a paste. The obtained paste was applied to an aluminum foil

having a thickness of 20 μm so that the density could be 2.5 mg/cm² andthe quantity of the positive active material to be housed in the batterycould be 5.3 g, and then dried at 150° C. to evaporate NMP. Theabove-described process was performed on both sides of the aluminumfoil, which then compressed and molded by roll pressing. Thus, apositive electrode plate, or the aluminum foil both sides of which werecoated with the positive composite layer, was prepared.

The positive and negative electrode plates thus prepared were overlappedand wound with a polyethylene separator, with continuous porosity havinga thickness of 20 μm and a porosity of 40%, being placed between them,and this element was housed in the case having 48 mm in height, 30 mm inwidth and 4.2 mm in thickness to form a non-aqueous electrolytesecondary battery of a prismatic type. Finally, the case was filled witha non-aqueous electrolyte solution; thus the non-aqueous electrolytesecondary battery of a prismatic type of Embodiment 1 was prepared. Theused non-aqueous electrolyte solution was prepared as follows: ethylenecarbonate (EC) and ethylmethyl carbonate (EMC) were mixed together in avolume ratio of 1:1, and 1 mol/l of LiPF₆ was dissolved in the mixedsolvent thus prepared. The rated capacity of the battery was 700 mAh.

Embodiment D2

The particle (S) and artificial graphite of a scale-like shape weregranulated in a weight mixture ratio of 1:1 by means of ball milling.The surface of the particle thus granulated was coated with carbon usingthe method (CVD) of thermally decomposing benzene gas under argonatmosphere at 1000° C., so that the composite particle (C) was prepared.The amount of the carbon coating was determined to be 20 wt. % to theweight of the composite particle (C). The number average particle sizeof the composite particle (C) coated with the carbon was 10 μm.

10 wt. % of the composite particle (C) and, as the carbon material (D),40 wt. % of MCMB, 30 wt. % of natural graphite and 20.0 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, the non-aqueous electrolyte secondarybattery of a prismatic type has an identical configuration to that ofEmbodiment D1. This battery was termed Embodiment D2.

Comparative Example D1

As a negative active material, 100 wt. % of natural graphite was used.Except for the above, the non-aqueous electrolyte secondary battery of aprismatic type has an identical configuration to that of Embodiment D1.This battery was termed Comparative Example D1.

Comparative Example D2

10 wt. % of the particle (S) having a number average particle size of 10μm, and, as the carbon material (D), 40 wt. % of MCMB, 30 wt. % ofnatural graphite and 20.0 wt. % of artificial graphite were used. Exceptfor the above, the non-aqueous electrolyte secondary battery of aprismatic type has an identical configuration to that of Embodiment D1.This battery was termed Comparative Example D2.

Comparative Example D3

As a negative active material, the composite particle (C) prepared inEmbodiment D1 was used alone. The amount of the carbon coating wasdetermined to be 20 wt. % to the weight of the composite particle (C).The number average particle size of the composite particle (C) was 10μm. Except for the above, the non-aqueous electrolyte secondary batteryof a prismatic type has an identical configuration to that of EmbodimentD1. This battery was termed Comparative Example D3.

Comparative Example D4

The surface of silicon particle was coated with carbon using the method(CVD) of thermally decomposing benzene gas under argon atmosphere at1000° C. The amount of the carbon coating was determined to be 20 wt. %to the total amount of the silicon particle and the carbon as coatingmaterial. The number average particle size of the silicon particlecoated with the carbon was 1 μm. Except for using such carbon-coated Siparticle as a negative active material, the non-aqueous electrolytesecondary battery of a prismatic type has an identical configuration tothat of Embodiment D1. This battery was termed Comparative Example D4.

The structures of the negative active materials used in Embodiments D1and D2 and Comparative Examples D1 to D4 were summarized in Table D1.

TABLE D1 Particle to be coated & coating material, Composition of andcomposition of composite particle (C) Number negative active Particle tobe coated Composition of (C) average material & coating material (wt. %)particle (wt. %) Particle Particle size of Composite Carbon to beCoating to be Coating (C) particle material coated material coatedmaterial (μm) (C) (D) EM D1 Particle(S) Carbon 80 20 10 10 90 EM D2Particle(S) + Carbon 40 + 40 20 10 10 90 Carbon CM D1 — — — — — 0 100 CMD2 Particle(S) — 100  — 10 10 90 CM D3 Particle(S) Carbon 80 20 10 100 0CM D4 Silicon Carbon 80 20  1 100 0 particleIn Tables D1 to D14, EM in the first column refers to Embodiment and CErefers to Comparative Example; for example, EM D1 refers to EmbodimentD1 and CE D1 refers to Comparative Example D1.

Embodiments D3 to D7, D56, and D57

Using the CVD method as described in Embodiment D1, the surface of theparticle (S) was coated with carbon, and the composite particle (C) wasprepared. The amount of the carbon coating was determined to be 20 wt. %to the weight of the composite particle (C). The number average particlesize of the carbon-coated SiO particle was 1 μm.

By mixing such composite particle (C) with the carbon material (D), anegative active material was prepared. As the carbon material (D), amixture of MCMB, natural graphite, and artificial graphite were used.Except for the composition of the negative active material, thenon-aqueous electrolyte secondary batteries of a prismatic type have anidentical configuration to that of Embodiment D1.

In Embodiments D3 to D7, the following compositions were used to preparethe negative active materials, respectively: 1 wt. % of the compositeparticle (C), and 40 wt. % of MCMB, 39 wt. % of natural graphite and 20wt. % of artificial graphite in Embodiment D3; 5 wt. % of the compositeparticle (C), and 40 wt. % of MCMB, 35 wt. % of natural graphite and 20wt. % of artificial graphite in Embodiment D4; 10 wt. % of the compositeparticle (C), and 40 wt. % of MCMB, 30 wt. % of natural graphite and 20wt. % of artificial graphite in Embodiment D5; 20 wt. % of the compositeparticle (C), and 40 wt. % of MCMB, 20 wt. % of natural graphite and 20wt. % of artificial graphite in Embodiment D6; and 30 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 10 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D7.

In Embodiments D56 and D57, the following compositions were used toprepare the negative active materials, respectively: 0.5 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 39.5 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D56; and 35wt. % of the composite particle (C), and 40 wt. % of MCMB, 5 wt. % ofnatural graphite and 20 wt. % of artificial graphite in Embodiment D57.

The structures of the negative active materials used in Embodiments D3to D7, D56, and D57 were summarized in Table D2.

TABLE D2 Composition Composition of negative of composite Number averageactive particle (C) particle size material (wt. %) (wt. %) of compositeCarbon Parti- Car- particle(C) Composite mate- cle (S) bon (μm)particle(C) rial(D) EM D56 80 20 1 0.5 99.5 EM D3 80 20 1 1 99 EM D4 8020 1 5 95 EM D5 80 20 1 10 90 EM D6 80 20 1 20 80 EM D7 80 20 1 30 70 EMD57 80 20 1 35 65

Embodiments D8 to D12

Using the CVD method as described in Embodiment D1; the surface of theparticle (S) was coated with carbon, and the composite particle (C) wasprepared. Having a negative active material which was prepared by mixingsuch composite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. The following compositionwas used to prepare the negative active material: 10 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 30 wt. % of naturalgraphite and 20 wt. % of artificial graphite.

Except for the composition of the composite particle (C), or theproportion of the weight of the carbon to the weight of the compositeparticle (C), the non-aqueous electrolyte secondary batteries of aprismatic type have an identical configuration to that of Embodiment D1.

In Embodiments D8 to D12, the respective carbon compositions in thecomposite particle (C) and the respective number average particle sizesof the composite particle (C) were as follows: 0.5 wt. % and 1.0 μm inEmbodiment D8; 1 wt. % and 1.0 μm in Embodiment D9; 10 wt. % and 1.0 μmin Embodiment D10; 30 wt. % and 1.1 μm in Embodiment D11; and 40 wt. %and 1.2 μm in Embodiment D12.

The structures of the negative active materials used in Embodiments D8to D12 were summarized in Table D3.

TABLE D3 Composition Composition of negative of composite Number averageactive particle (C) particle size material (wt. %) (wt. %) of compositeCarbon Parti- Car- particle(C) Composite mate- cle (S) bon (μm)particle(C) rial(D) EM D8 99.5 0.5 About 1.0 10 90 EM D9 99 1 About 1.010 90 EM D10 90 10 About 1.0 10 90 EM D11 70 30 About 1.0 10 90 EM D1260 40 About 1.0 10 90

Embodiments D13 to D16

Using the CVD method as described in Embodiment D1, the surface of theparticle (S) was coated with carbon, and the composite particle (C) wasprepared. The amount of the carbon coating was determined to be 20 wt. %to the weight of the composite particle (C). Having a negative activematerial which was prepared by mixing such composite particle (C) withthe carbon material (D), a non-aqueous electrolyte secondary battery wasproduced. The following composition was used to prepare the negativeactive material: 10 wt. % of the composite particle (C), and 40 wt. % ofMCMB, 30 wt. % of natural graphite and 20 wt. % of artificial graphite

Except for using the composite particle (C) having a different numberaverage particle size, the non-aqueous electrolyte secondary batteriesof a prismatic type have an identical configuration to that ofEmbodiment D1.

In Embodiments D13 to D16, the respective number average particle sizesof the composite particle (C) were as follows: 0.05 μm in EmbodimentD13, 0.1 μm in Embodiment D14, 20 μm in Embodiment D15, and 30 μm inEmbodiment D16.

The structures of the negative active materials used in Embodiments D13to D16 were summarized in Table D4, in which the structure used inEmbodiment D1 was also included.

TABLE D4 Composition Composition of negative of composite Number averageactive particle (C) particle size material (wt. %) (wt. %) of compositeCarbon Parti- Car- particle(C) Composite mate- cle (S) bon (μm)particle(C) rial(D) EM D13 80 20 0.05 10 90 EM D14 80 20 0.1 10 90 EM D180 20 10 10 90 EM D15 80 20 20 10 90 EM D16 80 20 30 10 90

Embodiments D17 to D21, D58, and D59

The particle (S) and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,using the method (CVD) as described in Embodiment D1, the surface of theparticle thus granulated was coated with carbon, and thecomposite-particle (C) was prepared. The amount of the carbon coatingwas determined to be 20 wt. % to the weight of the composite particle(C). The number average particle size of the composite particle (C) was20 μm.

Having a negative active material which was prepared by mixing suchcomposite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. As the carbon material (D),a mixture of MCMB, natural graphite, and artificial graphite were used.Except for the composition of the negative active material, thenon-aqueous electrolyte secondary batteries of a prismatic type have anidentical configuration to that of Embodiment D1.

In Embodiments D17 to D21, the following compositions were used toprepare the negative active materials, respectively: 1 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 39 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D17; 5 wt. %of the composite particle (C), and 40 wt. % of MCMB, 35 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D18; 10 wt. %of the composite particle (C), and 40 wt. % of MCMB, 30 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D19; 20 wt. %of the composite particle (C), and 40 wt. % of MCMB, 20 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D20; and 30wt. % of the composite particle (C), and 40 wt. % of MCMB, 10 wt. % ofnatural graphite and 20 wt. % of artificial graphite in Embodiment D21.

In Embodiments D58 and D59, the following compositions were used toprepare the negative active materials, respectively: 0.5 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 39.5 wt. % of naturalgraphite and 20 wt. % of artificial graphite in Embodiment D58; and 35wt. % of the composite particle (C), and 40 wt. % of MCMB, 5 wt. % ofnatural graphite and 20 wt. % of artificial graphite in Embodiment 59.

The structures of the negative active materials used in Embodiments D17to D21, D58 and D59 were summarized in Table D5.

TABLE D5 Number Composition of Composition of average Composition ofnegative granulated particle composite particle(C) particle activematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Carbon (C) particle material (S) Graphite particle coating(μm) (C) (D) EM D58 50 50 80 20 20 0.5 99.5 EM D17 50 50 80 20 20 1 99EM D18 50 50 80 20 20 5 95 EM D19 50 50 80 20 20 10 90 EM D20 50 50 8020 20 20 80 EM D21 50 50 80 20 20 30 70 EM D59 50 50 80 20 20 35 65

Embodiments D22 to D27

The particle (S) and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,using the method (CVD) as described in Embodiment D1, the surface of theparticle thus granulated was coated with carbon, and the compositeparticle (C) was prepared.

Having a negative active material which was prepared by mixing suchcomposite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. The following compositionwas used to prepare the negative active material: 10 wt. %

of the composite particle (C), and 40 wt. % of MCMB, 40 wt. % of naturalgraphite and 20 wt. % of artificial graphite. Except for the compositionof the composite particle (C), or the proportion of the weight of thecarbon to the weight of the composite particle (C), the non-aqueouselectrolyte secondary batteries of a prismatic type have an identicalconfiguration to that of Embodiment D1.

In Embodiments D22 to D27, the respective carbon compositions used inthe composite particle (C) and the respective number average particlesizes of the composite particle (C) were as follows: 0.5 wt. % andapproximately 20 μm in Embodiment D22; 1 wt. % and approximately 20 μmin Embodiment D23; 10 wt. % and approximately 20.4 μm in Embodiment D24;20 wt. % and approximately 20.8 μm in Embodiment D25; 30 wt. % andapproximately 21.2 μm in Embodiment D26; and 40 wt. % and approximately21.8 μm in Embodiment D27.

The structures of the negative active materials used in Embodiments D22to D27 were summarized in Table D6.

TABLE D6 Number Composition of Composition of average Mixture ratio ofnegative granulated particle composite particle(C) particle activematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Carbon (C) particle material (S) Graphite particle coating(μm) (C) (D) EM D22 50 50 99.5 0.5 20 10 90 EM D23 50 50 99 1 20 10 90EM D24 50 50 90 10 20.4 10 90 EM D25 50 50 80 20 20.8 10 90 EM D26 50 5070 30 21.2 10 90 EM D27 50 50 60 40 21.5 10 90

Embodiments D28 to D32

The particle (S) and graphite of a scale-like shape were granulatedusing a ball milling machine. After that, using the method (CVD) asdescribed in Embodiment D1, the surface of the particle thus granulatedwas coated with carbon, and the composite particle (C) was prepared. Theamount of the carbon coating was determined to be 20 wt. % to the weightof the composite particle (C). The number average particle size of thecomposite particle (C) was approximately 20 μm.

Having a negative active material which was prepared by mixing suchcomposite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. The following compositionwas used to prepare the negative active material: 10 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 40 wt. % of naturalgraphite and 20 wt. % of artificial graphite. Except for the mixtureratio of the particle (S) to the graphite of a scale-like shape in thegranulated particle, the non-aqueous electrolyte secondary batteries ofa prismatic type have an identical configuration to that of EmbodimentD1.

In Embodiments D28 to D32, the respective weight mixture ratios of theparticle (S) to the graphite of a scale-like shape in the granulatedparticle were as follows: 10:90 in Embodiment D28; 20:80 in EmbodimentD29; 40:60 in Embodiment D30; 70:30 in Embodiment D31; and 80:20 inEmbodiment D32.

The structures of the negative active materials used in Embodiments D28to D32 were summarized in Table D7, in which the structure used inEmbodiment D19 was also included.

TABLE D7 Number Composition of Composition of average Composition ofnegative granulated particle composite particle(C) particle activematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Carbon (C) particle material (S) Graphite particle coating(μm) (C) (D) EM D28 10 90 80 20 20 10 90 EM D29 20 80 80 20 20 10 90 EMD19 50 50 80 20 20 10 90 EM D30 40 60 80 20 20 10 90 EM D31 70 30 80 2020 10 90 EM D32 80 20 80 20 20 10 90

Embodiments D33 to D37

The particle (S) and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,using the method (CVD) as described in Embodiment D1, the surface of thegranulated composite particle was coated with carbon, and the compositeparticle (C) was prepared. The amount of the carbon coating wasdetermined to be 20 wt. % to the weight of the composite particle (C).

Having a negative active material which was prepared by mixing suchcomposite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. The following compositionwas used to prepare the negative active material: 10 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 40 wt. % of naturalgraphite and 20 wt. % of artificial graphite. Except for using compositeparticle (C) which is different in “the respective number averageparticle sizes”, the non-aqueous electrolyte secondary batteries of aprismatic type have an identical configuration to that of Embodiment D1.

In Embodiments D33 to D37, the respective number average particle sizesof the composite particle (C) were as follows: 0.05 μm in EmbodimentD33, 0.1 μm in Embodiment D34, 20 μm in Embodiment D35, 30 μm inEmbodiment D36, and 40 μm in Embodiment D37.

The structures of the negative active materials used in Embodiments D33to D37 were summarized in Table D8, in which the structure used inEmbodiment D2 was also included.

TABLE D8 Number Composition of Composition of average Composition ofnegative granulated particle composite particle(C) particle activematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Carbon (C) particle material (S) Graphite particle coating(μm) (C) (D) EM D33 50 50 80 20 0.05 10 90 EM D34 50 50 80 20 0.1 10 90EM D2 50 50 80 20 10 10 90 EM D35 50 50 80 20 20 10 90 EM D36 50 50 8020 30 10 90 EM D37 50 50 80 20 40 10 90

Embodiment D38

Carbon and the particle (S) were mixed and, using the mechanical millingmethod, the surface of the particle (S) was coated with the carbon; thusthe composite particle (C) was prepared. The amount of the carboncoating was determined to be 20 wt. % to the weight of the compositeparticle (C). The number average particle size of the composite particle(C) was 10 μm.

Using such composite particle (C), a non-aqueous electrolyte secondarybattery was produced. The following composition was used to

prepare the negative active material: 10 wt. % of the composite particle(C), and 40 wt. % of MCMB, 30 wt. % of natural graphite and 20 wt. % ofartificial graphite. Except for the negative active material, thenon-aqueous electrolyte secondary battery of a prismatic type has anidentical configuration to that of Embodiment D1. This battery wastermed Embodiment D38.

Embodiment D39

According to the same manner as described in Embodiment D38, the surfaceof the particle (S) was coated with carbon using the mechanical millingmethod, and the composite particle (C) was prepared. 10 wt. % of thecomposite particle (C), and, as the carbon material (D), 40 wt. % ofmeso carbon fiber containing boron, 30 wt. % of natural graphite and 20wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the negative active material, thenon-aqueous electrolyte secondary battery of a prismatic type has anidentical configuration to that of Embodiment D1. This battery wastermed Embodiment D39.

Embodiment D40

According to the same manner as described in Embodiment D38, the surfaceof the particle (S) was coated with carbon using the mechanical millingmethod, and the composite particle (C) was prepared. 10 wt. % of thecomposite particle (C), and, as the carbon material (D), 70 wt. % ofnatural graphite and 20 wt. % of artificial graphite were mixed togetherto prepare a negative active material. Except for the negative activematerial, the non-aqueous electrolyte secondary battery of a prismatictype has an identical configuration to that of Embodiment D1. Thisbattery was termed Embodiment D40.

Embodiment D41

Silicon particle and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,using the method (CVD) as described in Embodiment D1, the surface of theparticle thus granulated was coated with carbon, and the compositeparticle (C) was prepared. The amount of the carbon coating wasdetermined to be 20 wt. % to the weight of the composite particle (C).The number average particle size of the composite particle (C) was 20μm.

10 wt. % of the composite particle (C), and, as the carbon material (D),40 wt. % of MCMB, 30 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the composition of the negative active material,the non-aqueous electrolyte secondary battery of a prismatic type has anidentical configuration to that of Embodiment D1. This battery wastermed Embodiment D41.

Embodiment D42

ZrSi₂ particle and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. Except forthe above, the non-aqueous electrolyte secondary battery of a prismatictype has an identical configuration to that of Embodiment D1. Thisbattery was termed Embodiment D42.

Embodiment D43

The SiO particle consisting of amorphous single-phase (identified by thepeak of Si in X-ray diffraction pattern) and graphite of a scale-likeshape were granulated in a weight mixture ratio of 50:50 using a ballmilling machine. Except for the above, the non-aqueous electrolytesecondary battery of a prismatic type has an identical configuration tothat of Embodiment D41. This battery was termed Embodiment D43.

The structures of the negative active materials used in Embodiments D38to D43 were summarized in Tables D9 and D10. In the “MCMB” column ofEmbodiment D39 in Table 10, the value of boron-containing meso carbonfiber is entered.

TABLE D9 Particle to be coated Composition Mixture ratio (wt. %)Silicon- Silicon- Carbon containing containing coating particle Carbonparticle Carbon method EM SiO — 100 — Mechanical D38 milling EM SiO —100 — Mechanical D39 milling EM SiO — 100 — Mechanical D40 milling EM SiScale-like 50 50 CVD 41 graphite EM ZrSi₂ Scale-like 50 50 CVD D42graphite EM amorphous Scale-like 50 50 CVD D43 single- graphite phaseSiO

TABLE D10 Number Composition of average composite particle Compositionof negative particle(C) (wt. %) size of active material (wt. %) CoatedCarbon (C) Composite MC Natural Artificial particle coating (μm)particle(C) MB graphite graphite EM D38 80 20 10 10 40 30 20 EM D39 8020 10 10 40 30 20 EM D40 80 20 10 10 0 70 20 EM D41 80 20 20 10 40 30 20EM D42 80 20 20 10 40 30 20 EM D43 80 20 20 10 40 30 20

Embodiments D44 to D49

The particle (S) and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,the granulated particle was immersed in an electrolytic bath, and byelectroless plating, the surface of such particle was coated with copper(Cu); thus, the composite particle (C) was prepared.

Having a negative active material which was prepared by mixing suchcomposite particle (C) with the carbon material (D), a non-aqueouselectrolyte secondary battery was produced. The following compositionwas used to prepare the negative active material: 10 wt. % of thecomposite particle (C), and 40 wt. % of MCMB, 40 wt. % of naturalgraphite and 20 wt. % of artificial graphite. Except for the amount ofCu coating to the weight of the composite particle (C), the non-aqueous

electrolyte secondary batteries of a prismatic type have an identicalconfiguration to that of Embodiment D1.

In Embodiments D44 to D49, the respective amounts of Cu coating in thecomposite particle (C) and the respective number average particle sizesof the composite particle (C) were as follows: 0.5 wt. % andapproximately 20 μm in Embodiment D44; 1 wt. % and approximately 20 μmin Embodiment D45; 10 wt. % and approximately 20.5 μm in Embodiment D46;20 wt. % and approximately 20.9 μm in Embodiment D47; 30 wt. % andapproximately 21.5 μm in Embodiment D48; and 40 wt. % and approximately21.7 μm in Embodiment D49.

The structures of the negative active materials used in Embodiments D44to D49 were summarized in Table D11.

TABLE D11 Number Composition of Composition of Composition of averagenegative active granulated particle composite particle(C) particlematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Cu (C) particle material (S) Graphite particle coating (μm)(C) (D) EM D44 50 50 99.5 0.5 20 10 90 EM D45 50 50 99 1 20 10 90 EM D4650 50 90 10 20.5 10 90 EM D47 50 50 80 20 20.9 10 90 EM D48 50 50 70 3021.5 10 90 EM D49 50 50 60 40 21.7 10 90

Embodiments D50 to D55

The particle (S) and graphite of a scale-like shape were granulated in aweight mixture ratio of 50:50 using a ball milling machine. After that,the granulated particle was immersed in an electrolytic bath, and byelectroless plating, the surface of such particle was coated with nickel(Ni); thus, the composite particle (C) was prepared. Except for theabove, the non-aqueous electrolyte secondary batteries of a prismatictype have an identical configuration to that of Embodiment D44.

In Embodiments D50 to D55, the respective amounts of Ni coating in thecomposite particle (C) and the respective number average particle sizesof the composite particle (C) were as follows: 0.5 wt. % andapproximately 20 μm in Embodiment D50; 1 wt. % and approximately 20.1 μmin Embodiment D51; 10 wt. % and approximately 20.4 μm in Embodiment D52;20 wt. % and approximately 20.8 μm in Embodiment D53; 30 wt. % andapproximately 21.3 μm in Embodiment D54; and 40 wt. % and approximately21.5 μm in Embodiment D55.

The structures of the negative active materials used in Embodiments D50to D55 were summarized in Table D12.

TABLE D12 Number Composition of Composition of Composition of averagenegative active granulated particle composite particle(C) particlematerial (wt. %) (wt. %) (wt. %) size of Composite Carbon ParticleGranulated Ni (C) particle material (S) Graphite particle coating (μm)(C) (D) EM D50 50 50 99.5 0.5 20 10 90 EM D51 50 50 99 1 20.1 10 90 EMD52 50 50 90 10 20.4 10 90 EM D53 50 50 80 20 20.8 10 90 EM D54 50 50 7030 21.3 10 90 EM D55 50 50 60 40 21.5 10 90

(Charge/Discharge Measurement)

Each battery prepared as above was charged at a constant current of 700mA at a temperature of 25° C. until the voltage reached 4.2 V,subsequently charged at a constant voltage of 4.2 V for 2 hours, andthen discharged at a constant current of 700 mA until the voltagedropped to 2.0 V. These steps were taken as one cycle and thecharge/discharge test was repeated 500 cycles. Table D13 shows thedischarge capacity at the 1^(st) cycle (initial discharge) and thecapacity retention ratio for the batteries of Embodiments D1 to D43, D56to D59, and Comparative Examples D1 to D4; and Table D14 shows those forthe batteries of Embodiments D44 to D55. Here, “capacity retentionratio” means the ratio of the discharge capacity at the 500^(th) cycleto the one at the 1^(st) cycle (expressed in percentage).

TABLE D13 Discharge Capacity capacity retention (mAh) ratio (%) EM D1749 75 EM D2 742 84 EM D3 730 80 EM D4 750 86 EM D5 752 85 EM D6 755 76EM D7 754 68 EM D8 760 56 EM D9 752 72 EM D10 754 86 EM D11 739 78 EMD12 700 76 EM D13 760 59 EM D14 751 71 EM D15 753 69 EM D16 755 54 EMD17 719 83 EM D18 732 82 EM D19 742 84 EM D20 747 79 EM D21 741 74 EMD22 745 61 EM D23 743 74 EM D24 740 78 EM D25 736 82 EM D26 728 80 EMD27 680 78 EM D28 701 80 EM D29 739 82 EM D30 743 81 EM D31 747 77 EMD32 732 51 EM D33 741 52 EM D34 745 69 EM D35 744 73 EM D36 743 79 EMD37 740 57 EM D38 750 69 EM D39 743 83 EM D40 747 53 EM D41 741 74 EMD42 742 76 EM D43 751 65 CE D1 635 80 CE D2 630 10 CE D3 370 79 CE D4820 9 EM D56 690 78 EM D57 754 18 EM D58 672 79 EM D59 739 22

TABLE D14 Initial Capacity capacity retention (mAh) ratio (%) EM D44 73549 EM D45 734 78 EM D46 729 79 EM D47 723 82 EM D48 715 81 EM D49 689 78EM D50 732 52 EM D51 732 75 EM D52 715 77 EM D53 712 78 EM D54 709 82 EMD55 662 77

From the comparison of the results of Embodiments D1 to D43, D56 to D59,and Comparative Examples D1 to D4, the following were revealed.

Embodiments D1, D2, and Comparative Examples D1 to D4 were compared. InComparative Example D1, where conventional graphite alone was used asthe negative active material, the initial

capacity was 635 mAh and the capacity retention ratio was 80%;meanwhile, in Comparative Example D2, where a mixture of SiO and carbonmaterial was used as the negative active material, the initial capacitywas about the same level but the capacity retention ratio was extremelylow. In addition, in Comparative Example D3, where the SiO particlealone, the surface of which was coated with carbon, was used as thenegative active material, the capacity retention ratio was about thesame level but the initial capacity was much smaller, as compared toComparative Example D1. Moreover, in Comparative Example D4, where theSi particle alone, the surface of which was coated with carbon, was usedas the negative active material, the initial capacity was larger but thecapacity retention ratio was extremely lower, as compared to ComparativeExample D1.

In addition, in the comparison of Embodiments D1 and D2 with ComparativeExamples D1 to D4, the initial capacities were larger and the capacityretention ratios were superior in Embodiments D1 and D2. As describedpreviously, in Embodiment D1, a mixture of carbon-coated SiO and carbonmaterial was used as the negative active material; and in Embodiment D2,the surface of the mixed particle of SiO particle and scale-likeartificial graphite was coated with carbon to prepare compositeparticle, and a mixture of such composite particle and carbon materialwas used as the negative active material. From these results, it isbelieved that electronic conductivity improves by coating the surface ofSiO particle with carbon.

Next, Embodiments D3 to D7, D56, and D57 were compared; where a mixtureof carbon-coated SiO particle and carbon material was used as thenegative active material and a different mixture ratio between thecarbon-coated SiO particle and the carbon material was applied to eachembodiment. In Embodiments D3 to D7, where the compositions of thecarbon-coated SiO particle in the total amount of the carbon-coated SiOparticle and the carbon material fall within the range of 1 to 30 wt. %,the initial capacities were large and the capacity retention ratios weresignificantly high, too. Meanwhile, in Embodiment D56, where thecomposition of the carbon-coated SiO particle stood at 0.5 wt. %, thecontent of the SiO particle highly capable of absorbing lithium was toosmall to attain a sufficient initial

capacity for the battery; and in Embodiment D57, where the compositionof the carbon-coated SiO particle stood at 35 wt. %, theexpansion/contraction of the negative electrode plate was so large thatcurrent collection performance was caused to be deteriorated and thecapacity retention ratio became significantly low. Therefore, from theviewpoint of the cycle performance and discharge capacity, when amixture of the carbon-coated SiO particle and the carbon material isused as the negative active material, it is preferable that thecomposition of the carbon-coated SiO particle in the total amount of thecarbon-coated SiO particle and the carbon material lie in the range of 1to 30 wt. %.

Next, Embodiments D8 to D12 were compared; where the composition of thecarbon with which the surface of SiO particle was coated in the totalamount of the SiO particle and the carbon on the surface of the SiOparticle was varied. In Embodiments D9 to D11, where the compositions ofthe carbon fall within the range of 1 to 30 wt. %, the initialcapacities were large and the capacity retention ratios were high, too.Meanwhile, in Embodiment 8, where the composition of the carbon was 0.5wt. %, the desired effect was hardly obtained because the capacityretention ratio was rather low, and in Embodiment D12, where thecomposition of the carbon was 40 wt. %, the content of the SiO particlehighly capable of absorbing lithium was small, so that the initialcapacity became rather low. Therefore, it is more preferable that thecomposition of the carbon with which the surface of the SiO particle iscoated in the total amount of the SiO particle and the carbon on thesurface of the SiO particle lie in the range of 1 to 30 wt. %.

Next, Embodiments D1, and D13 to D16 were compared; where the numberaverage particle size of the SiO particle, the surface of which wascoated with carbon, was varied. In Embodiments D1, D14 and D15, wherethe number average particle sizes were in the range of 0.1 to 20 μm,large initial capacities and high capacity retention ratios wereattained. Meanwhile, in Embodiment D13, where the number averageparticle size was 0.05 μm, it was difficult to prepare and handle theactive material, so that the capacity retention ratio became rather low.In Embodiment D16, in addition, where the number average particle sizewas 30 μm, the negative electrode plate was hard to be

prepared, so that the capacity retention ratio became rather low.Therefore, it is more preferable that the number average particle sizeof the SiO particle, the surface of which is coated with carbon, lie inthe range of 0.1 to 20 μm.

Hereinafter, the results will be compared in terms of the followingcase; the composite particle was prepared by mixing SiO particle andgraphite of a scale-like shape, the surface of the composite particlewas coated with carbon, and a mixture of the carbon-coated compositeparticle and carbon material was used as the negative active material.

First, Embodiments D17 to D21, D58, and D59 were compared, where adifferent mixture ratio of the carbon-coated composite particle to thetotal amount of the carbon-coated composite particle and the carbonmaterial was applied to each embodiment. In Embodiments D17 to D21,where the compositions of the carbon-coated composite particle fellwithin the range of 1 to 30 wt. %, the initial capacities were large andthe capacity retention ratios were high, too. Meanwhile, in EmbodimentD58, where the composition of the carbon-coated composite particle was0.5 wt. %, the content of the SiO particle highly capable of absorbinglithium was too small to attain a sufficient initial capacity for abattery; and in Embodiment D59, where the composition of thecarbon-coated composite particle stood at 35 wt. %, theexpansion/contraction of the negative electrode plate was so large thatthe current collection performance was caused to be deteriorated and thecapacity retention ratio became significantly low. Therefore, for theenhancement of both initial capacity and capacity retention ratio, it ispreferable that the composition of the carbon-coated composite particlein the total amount of the carbon-coated composite particle and thecarbon material lie in the range of 1 to 30 wt. %.

Next, Embodiments D22 to D27 were compared; where a different mixtureratio of the carbon on the composite particle, which was prepared usingSiO particle and graphite of a scale-like shape, to the total amount ofthe carbon on the composite particle, the SiO particle, and the graphiteof a scale-like shape was applied to each embodiment. In Embodiments D23to D26, where the compositions of the carbon fell within the range of 1to 30 wt. %, large initial capacities and high capacity retention ratioswere attained. Meanwhile, in Embodiment D22, where the composition ofthe carbon was 0.5 wt. %, the capacity retention ratio was rather low,and in Embodiment D27, where the composition of the carbon was 40 wt. %,the content of the SiO particle highly capable of absorbing lithium wassmall, so that the initial capacity was rather small. Therefore, it ispreferable that the composition of the carbon on the composite particlein the total amount of the carbon on the composite particle, the SiOparticle, and the graphite of a scale-like shape lie in the range of 1to 30 wt. %.

Next, Embodiments D19, and D28 to D32 were compared, where a differentmixture′composition of SiO particle in the total amount of the SiOparticle and the graphite of a scale-like shape was applied to eachembodiment. In Embodiments D19, and D29 to D31, where the compositionsof SiO particle fell within the range of 20 to 70 wt. %, large initialcapacities and high capacity retention ratios were attained. Meanwhile,in Embodiment D28, where the composition of the SiO particle was 10 wt.%, the content of the SiO particle highly capable of absorbing lithiumwas small, so that the initial capacity became small, and in EmbodimentD32, where the composition of the SiO particle was 80 wt. %, theinfluence of the SiO particle on the volume expansion/contraction duringthe charge/discharge was so large as to cause a small decrease in thecapacity retention ratio. Therefore, it is preferable that thecomposition of the SiO particle in the total amount of the SiO particleand the graphite of a scale-like shape lie in the range of 20 to 70 wt.%.

Next, Embodiments D2, and D33 to D37 were compared; where the numberaverage particle size of the carbon-coated composite particle wasvaried. In Embodiments D2, and D34 to D36, where the number averageparticle sizes were in the range of 0.1 to 30 μm, large initialcapacities and high capacity retention ratios were attained. Meanwhile,in Embodiment D33, where the number average particle size was 0.05 μm,it was difficult to prepare and handle the active material, so that thecapacity retention ratio became rather small. In Embodiment D37, inaddition, where the number average particle size was 40 μm, the negativeelectrode plate was hard to be prepared, and the capacity retentionratio became rather small. Therefore, it is more

preferable that the number average particle size of the carbon-coatedcomposite particle lie in the range of 0.1 to 30 μm.

Hereinafter, the results will be compared in terms of the process ofpreparing the composite particle, or the composition of the carbonmaterial in the negative active materials.

Embodiments D38 to D40 were compared; where mechanical milling methodwas employed for coating the surface of SiO particle with carbon, andthe composition of the carbon material to be mixed with suchcarbon-coated SiO particle was varied. In the comparison of EmbodimentD38 with Embodiment D5, where CVD method was employed for coating thesurface of SiO particle with carbon, large initial capacities wereattained in both methods; however, a larger capacity retention ratio wasobtained by using CVD method in Embodiment D5. It is believed that thereason for this may be that the surface can be coated more uniformly bythe use of CVD method. In the comparison between Embodiment D38, whereMCMB was contained in the carbon material, and Embodiment D39, whereboron-containing meso carbon fiber was contained in the carbon material,large initial capacities and high capacity retention ratios wereobtained in both batteries. However, in Embodiment 40, where naturalgraphite and artificial graphite, with no MCMB, were used as the carbonmaterial, the capacity retention ratio became rather low.

In addition, Embodiments D41 to D43 were compared. In Embodiments D41and D42, where Si and ZrSi₂ were used respectively as thesilicon-containing material, in stead of SiO, large initial capacitiesand high capacity retention ratios were attained. Moreover, inEmbodiment D43, where amorphous single-phase SiO was used as thesilicon-containing material, a large initial capacity and a highcapacity retention ratio were obtained. Thus, when SiO disproportionatedto microcrystalline Si and amorphous SiO₂, and when a diffraction peakappeared in a range of diffraction angle (2θ) from 46° to 49° and thehalf width of the main diffraction peak appearing in said range wassmaller than 3° (2θ) in X-ray diffraction pattern with the use of theCuKα radiation, large initial capacities and extremely high capacityretention ratios were achieved.

Finally, the results will be compared in terms of the following

case: as a core material, composite particle was prepared by mixing SiOparticle (S) and graphite of a scale-like shape; the surface of thecomposite particle was coated with copper (Cu) or nickel (Ni); and themixture ratio of the Cu or Ni on the composite particle to the totalamount of the Cu or Ni on the composite particle, the SiO particle, andthe graphite of a scale-like shape was varied.

Embodiments D44 to D49 were compared, where Cu was used as coatingmaterial. In Embodiments D45 to D48, where the compositions of the Cu onthe composite particle fell within the range of 1 to 30 wt. %, largeinitial capacities and high capacity retention ratios were attained.Meanwhile, in Embodiment D44, where the composition of the Cu was 0.5wt. %, the capacity retention ratio became rather low, and in EmbodimentD49, where the composition of the Cu was 40 wt. %, the content of theSiO particle highly capable of absorbing lithium was small, so that theinitial capacity became rather small. Therefore, it is preferable thatthe composition of the Cu on the composite particle in the total amountof the Cu on the composite particle, the SiO particle, and the graphiteof a scale-like shape lie in the range of 1 to 30 wt. %.

In the comparison among Embodiments D50 to D55, where Ni was used as thecoating material, similar results to those in the case where Cu was usedwere obtained in the relationship of the coating amount to the initialcapacity and the capacity retention ratio. In addition, the results wereconsistent with those obtained in Embodiments D22 to D27, where carbonwas used as the coating material.

Embodiment E Embodiment E1

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so thatcomposite particle (e1) was prepared. The proportion of the electronicconductive additive (B) was determined to be 0.5 wt. % to the total massof the composite particle (e1). The number average particle size of theproduct (e1) was 10 μm.

Next, with the use of such composite particle (e1), a

non-aqueous electrolyte secondary battery was produced according to thefollowing manner. First, 95.5 wt. % of the composite particle (e1) and,as the carbon material (D), 0.5 wt. % of artificial graphite were mixedtogether to prepare a negative active material. 97 wt. % of the obtainednegative active material, 2 wt. % of styrene-butadiene rubber (SBR), and1 wt. % of carboxymethylcellulose (CMC) were mixed in water to prepare apaste. The obtained paste was applied to a copper foil having athickness of 15 μm so that the total amount of the negative activematerial to be housed in the battery could be 2.0 g, and then dried at150° C. to evaporate water. This process was performed on both sides ofthe copper foil, which then compressed and molded by roll pressing.Thus, a negative electrode having the negative composite layer on eitherside was prepared.

Next, 90 wt. % of lithium cobalt oxide, 5 wt. % of acetylene black, and5 wt. % of poly(vinylidene fluoride) (PVdF) were dispersed in NMP tomake a paste. The obtained paste was applied to an aluminum foil havinga thickness of 20 μm so that the total amount of the positive activematerial to be housed in the battery could be 5.3 g, and then dried at150° C. to evaporate NMP. The above-described process was performed onboth sides of the aluminum foil, which then compressed and molded byroll pressing. Thus, a positive electrode having the positive compositelayer on either side was prepared.

The positive and negative electrodes thus prepared were overlapped andwound with a polyethylene separator, with continuous porosity having athickness of 20 μm and a porosity of 40%, being placed between them, andthis element was housed in the case having 48 mm in height, 30 mm inwidth, and 4.2 mm in thickness to form a prismatic-type battery having arated capacity of 700 mA. Finally, the case was filled with anon-aqueous electrolyte solution; thus Battery (A1) of Embodiment 1 wascompleted. The non-aqueous electrolyte solution was prepared as follows:ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed togetherin a volume ratio of 1:1, and 1 mol dm⁻³ of LiPF₆ was dissolved in themixed solvent thus prepared.

Embodiment E2

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so thatcomposite particle (e2) was prepared. The proportion of the electronicconductive additive (B) was determined to be 5.0 wt. % to the total massof the composite particle (e2). The number average particle size of thecomposite particle (e2) was 10.9 μm. Except for using such compositeparticle (e2), Battery (A2) has an identical configuration to that ofEmbodiment E1. This battery was termed Embodiment E2.

Embodiment E3

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so thatcomposite particle (e3) was prepared. The proportion of the electronicconductive additive (B) was determined to be 10.0 wt. % to the totalmass of the composite particle (e3). The number average particle size ofthe composite particle (e3) was 11.5 μm. Except for using such compositeparticle (e3), Battery (A3) has an identical configuration to that ofEmbodiment E1. This battery was termed Embodiment E3.

Embodiment E4

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so thatcomposite particle (e4) was prepared. The proportion of the electronicconductive additive (B) was determined to be 20.0 wt. % to the totalmass of the composite particle (e4). The number average particle size ofthe composite particle (e4) was 13.0 μm. Except for using such compositeparticle (e4), Battery (A4) has an identical configuration to that ofEmbodiment E1. This battery was termed Embodiment E4.

Embodiment E5

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so thatcomposite particle (e5) was prepared. The proportion of the electronicconductive additive (B) was determined to be 30.0 wt. % to the totalmass of the composite particle (e5). The number average particle size ofthe composite particle (e5) was 14.5 μm. Except for using such compositeparticle (e5), Battery (A5) has an identical configuration to that ofEmbodiment E1. This battery was termed Embodiment E5.

Embodiment E6

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so thatcomposite particle (e6) was prepared. The proportion of the electronicconductive additive (B) was determined to be 38.0 wt. % to the totalmass of the composite particle (e6). The number average particle size ofthe composite particle (e6) was 16.1 μm. Except for using such compositeparticle (e6), Battery (A6) has an identical configuration to that ofEmbodiment E1. This battery was termed Embodiment E6.

Embodiment E7

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so that aproduct (e7) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 40.0 wt. % to the total mass of theproduct (e7). The number average particle size of the product (e7) was16.4 μm. Except for using this product (e7), Battery (A7) has anidentical configuration to that of Embodiment E1. This battery wastermed Embodiment E7.

Comparative Example E1

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so that aproduct (e8) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 0.1 wt. % to the total mass of theproduct (e8). The number average particle size of the product (e8) was9.8 μm. Except for using this product (e8), Battery (B1) has anidentical configuration to that of Embodiment E1. This battery wastermed Comparative Example E1.

Embodiment E153

The surface of Si particle (s) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing benzene gas under argon atmosphere at 1000° C., so that aproduct (e9) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 50.0 wt. % to the total mass of theproduct (e9). The number average particle size of the product (e9) was18.1 μm. Except for using this product (e9), Battery (B2) has anidentical configuration to that of Embodiment E1. This battery wastermed Embodiment E153.

Embodiment E8

80.0 wt. % of the product (e1) and, as the carbon material (D), 20.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A8) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E8.

Embodiments E9 to 14

Except for using the product (e2), Battery (A9) has an identicalconfiguration to that of Embodiment E8. This battery was termedEmbodiment E9. Except for using the product (e3), Battery (A10) has anidentical configuration to that of Embodiment E8. This battery wastermed Embodiment E10. Except for using the product (e4), Battery (A11)has an identical configuration to that of Embodiment E8. This batterywas termed Embodiment E11. Except for using the product (e5), Battery(A12) has an identical configuration to that of Embodiment E8. Thisbattery was termed Embodiment E12. Except for using the product (e6),Battery (A13) has an identical configuration to that of Embodiment E8.This battery was termed Embodiment E13. And, except for using theproduct (e7), Battery (A14) has an identical configuration to that ofEmbodiment E8. This battery was termed Embodiment E14.

Comparative Example E2

Except for using the product (e8), Battery (B3) has an identicalconfiguration to that of Embodiment E8. This battery was termedComparative Example E2.

Embodiment E154

Except for using the product (e9), Battery (B4) has an identicalconfiguration to that of Embodiment E8. This battery was termedEmbodiment E154.

Embodiment E15

99.9 wt. % of the product (e1) and, as the carbon material (D),

0.1 wt. % of artificial graphite were mixed together to prepare anegative active material. Except for the above, Battery (A15) has anidentical configuration to that of Embodiment E1. This battery wastermed Embodiment E15.

Embodiment E16

99.0 wt. % of the product (e1) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A16) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E16.

Embodiment E17

95.0 wt. % of the product (e1) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A17) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E17.

Embodiment E18

90.0 wt. % of the product (e1) and, as the carbon material (D), 10.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A18) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E18.

Embodiment E19

85.0 wt. % of the product (e1) and, as the carbon material (D), 15.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A19) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E19.

Embodiment E20

75.0 wt. % of the product (e1) and, as the carbon material (D), 25.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A20) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E20.

Embodiment E21

99.9 wt. % of the product (e4) and, as the carbon material (D), 0.1 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A21) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E21.

Embodiment E22

99.0 wt. % of the product (e4) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A22) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E22.

Embodiment E23

95.0 wt. % of the product (e4) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A23) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E23.

Embodiment E24

90.0 wt. % of the product (e4) and, as the carbon material (D), 10.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A24) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E24.

Embodiment E25

85.0 wt. % of the product (e4) and, as the carbon material (D), 15.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A25) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E25.

Embodiment E26

75.0 wt. % of the product (e4) and, as the carbon material (D), 25.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A26) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E26.

Embodiment E27

99.9 wt. % of the product (e7) and, as the carbon material (D), 0.1 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A27) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E27.

Embodiment E28

99.0 wt. % of the product (e7) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A28) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E28.

Embodiment E29

95.0 wt. % of the product (e7) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A29) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E29.

Embodiment E30

90.0 wt. % of the product (e7) and, as the carbon material (D), 10.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A30) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E30.

Embodiment E31

85.0 wt. % of the product (e7) and, as the carbon material (D), 15.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A31) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E31.

Embodiment E32

75.0 wt. % of the product (e7) and, as the carbon material (D), 25.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A32) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E32.

Embodiment E33

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e10)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 0.5 wt. % and 59.5 wt.%, respectively, to the total mass of the product (e10). The numberaverage particle size of the product (e10) was 15 μm.

Except for using the product (e10), Battery (A33) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E33.

Embodiment E34

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e11)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 5.0 wt. % and 59.0 wt.%, respectively, to the total mass of the product (e11). The numberaverage particle size of the product (e11) was 15.5 μm.

Except for using the product (e11), Battery (A34) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E34.

Embodiment E35

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e12)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 10.0 wt. % and 50.0wt. %, respectively, to the total mass of the product (e12). The numberaverage particle size of the product (e12) was 16.1 μm.

Except for using the product (e12), Battery (A35) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E35.

Embodiment E36

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e13)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 20.0 wt. % and 40.0wt. %, respectively, to the total mass of the product (e13). The numberaverage particle size of the product (e13) was 17.2 μm.

Except for using the product (e13), Battery (A36) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E36.

Embodiment E37

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e14)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 30.0 wt. % and 30.0wt. %, respectively, to the total mass of the product (e14). The numberaverage particle size of the product (e14) was 18.1 μm.

Except for using the product (e14), Battery (A37) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E37.

Embodiment E38

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e15)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 38.0 wt. % and 22.0wt. %, respectively, to the total mass of the product (e15). The numberaverage particle size of the product (e15) was 19.5 μm.

Except for using the product (e15), Battery (A38) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E38.

Embodiment E39

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e16)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 40.0 wt. % and 20.0wt. %, respectively, to the total mass of the product (e16). The numberaverage particle size of the product (e16) was 20.4 μm.

Except for using the product (e16), Battery (A39) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E39.

Comparative Example E3

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e17)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 0.1 wt. % and 59.9 wt.%, respectively, to the total mass of the product (e17). The numberaverage particle size of the product (e17) was 14.8 μm.

Except for using the product (e17), Battery (B5) has an identicalconfiguration to that of Embodiment E1. This battery was termedComparative Example E3.

Embodiment E155

By mechanochemical reaction between Si particle (s) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e18)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 50.0 wt. % and 10.0wt. %, respectively, to the total mass of the product (e18). The numberaverage particle size of the product (e18) was 21.5 μm.

Except for using the product (e18), Battery (B6) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E155.

Embodiment E40

80.0 wt. % of the product (e10) and, as the carbon material (D), 20.0wt. % of artificial graphite were mixed together to prepare negativeactive material. Except for the above, Battery (A40) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E40.

Embodiment E41

Except for using the product (e11), Battery (A41) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E41.

Embodiment E42

Except for using the product (e12), Battery (A42) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E42.

Embodiment E43

Except for using the product (e13), Battery (A43) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E43.

Embodiment E44

Except for using the product (e14), Battery (A44) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E44.

Embodiment E45

Except for using the product (e15), Battery (A45) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E45.

Embodiment E46

Except for using the product (e16), Battery (A46) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E46.

Comparative Example E4

Except for using the product (e17), Battery (B7) has an identicalconfiguration to that of Embodiment E40. This battery was termedComparative Example E4.

Embodiment E156

Except for using the product (e18), Battery (B8) has an identicalconfiguration to that of Embodiment E40. This battery was termedEmbodiment E156.

Embodiment E47

99.9 wt. % of the product (e10) and, as the carbon material (D), 0.1 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A47) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E47.

Embodiment E48

99.0 wt. % of the product (e10) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A48) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E48.

Embodiment E49

95.0 wt. % of the product (e10) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A49) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E49.

Embodiment E50

90.0 wt. % of the product (e10) and, as the carbon material (D), 10.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A50) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E50.

Embodiment E51

85.0 wt. % of the product (e10) and, as the carbon material (D), 15.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A51) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E51.

Embodiment E52

75.0 wt. % of the product (e10) and, as the carbon material (D), 25.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A52) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E52.

Embodiment E53

99.9 wt. % of the product (e13) and, as the carbon material (D), 0.1 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A53) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E53.

Embodiment E54

99.0 wt. % of the product (e13) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A54) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E54.

Embodiment E55

95.0 wt. % of the product (e13) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A55) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E55.

Embodiment E56

90.0 wt. % of the product (e13) and, as the carbon material (D), 10.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A56) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E56.

Embodiment E57

85:0 wt. % of the product (e13) and, as the carbon material (D), 15.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A57) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E57.

Embodiment E58

75.0 wt. % of the product (e13) and, as the carbon material (D), 25.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A58) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E58.

Embodiment E59

99.9 wt. % of the product (e16) and, as the carbon material (D), 0.1 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A59) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E59.

Embodiment E60

99.0 wt. % of the product (e16) and, as the carbon material (D), 1.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A60) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E60.

Embodiment E61

95.0 wt. % of the product (e16) and, as the carbon material (D), 5.0 wt.% of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A61) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E61.

Embodiment E62

90.0 wt. % of the product (e16) and, as the carbon material (D), 10.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A62) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E62.

Embodiment E63

85.0 wt. % of the product (e16) and, as the carbon material (D), 15.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A63) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E63.

Embodiment E64

75.0 wt. % of the product (e16) and, as the carbon material (D), 25.0wt. % of artificial graphite were mixed together to prepare a negativeactive material. Except for the above, Battery (A64) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E64.

Embodiment E65

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e17) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 0.5 wt. % to the total mass of theproduct (e17). The number average particle size of the product (e17) was0.9 μm.

30 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 10 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A65) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E65.

Embodiment E66

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e18) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 1.0 wt. % to the total mass of theproduct (e18). The number average particle size of the product (e18) was0.9 μm.

Except for using this product (e18), Battery (A66) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E66.

Embodiment E67

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e19) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 10.0 wt. % to the total mass of theproduct (e19). The number average particle size of the product (e19) was1.0 μm.

Except for using this product (e19), Battery (A67) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E67.

Embodiment E68

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e20) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 20.0 wt. % to the total mass of theproduct (e20). The number average particle size of the product (e20) was1.0 μm.

Except for using this product (e20), Battery (A68) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E68.

Embodiment E69

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e21) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 30.0 wt. % to the total mass of theproduct (e21). The number average particle size of the product (e21) was1.1 μm.

Except for using this product (e21), Battery (A69) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E69.

Embodiment E70

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e22) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 38.0 wt. % to the total mass of theproduct (e22). The number average particle size of the product (e22) was1.2 μm.

Except for using this product (e22), Battery (A70) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E70.

Embodiment E71

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e23) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 40.0 wt. % to the total mass of theproduct (e23). The number average particle size of the product (e23) was1.4 μm.

Except for using this product (e23), Battery (A71) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E71.

Comparative Example E5

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 1000° C., so that aproduct (e24) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 0.1 wt. % to the total mass of theproduct (e24). The number average particle size of the product (e24) was0.8 μm.

Except for using this product (e24), Battery (B9) has an identicalconfiguration to that of Embodiment E65. This battery was termedComparative Example E5.

Embodiment E157

The surface of SiO particle (t) was supported with carbon, as theelectronic conductive additive (B), using the method (CVD) of thermallydecomposing toluene gas under argon atmosphere at 100000, so that aproduct (e25) was prepared. The proportion of the electronic conductiveadditive (B) was determined to be 50.0 wt. % to the total mass of theproduct (e25). The number average particle size of the product (e25) was1.5 μm.

Except for using this product (e25), Battery (B10) has an identicalconfiguration to that of Embodiment E65. This battery was termedEmbodiment E157.

Embodiment E72

10 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 30 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A72) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E72.

Embodiment E73

Except for using the product (e18), Battery (A73) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E73.

Embodiment E74

Except for using the product (e19), Battery (A74) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E74.

Embodiment E75

Except for using the product (e20), Battery (A75) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E75.

Embodiment E76

Except for using the product (e21), Battery (A76) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E76.

Embodiment E77

Except for using the product (e22), Battery (A77) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E77.

Embodiment E78

Except for using the product (e23), Battery (A78) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E78.

Comparative Example E6

Except for using the product (e24), Battery (B11) has an identicalconfiguration to that of Embodiment E72. This battery was termedComparative Example E6.

Embodiment E158

Except for using the product (e25), Battery (B12) has an identicalconfiguration to that of Embodiment E72. This battery was termedEmbodiment E158.

Embodiment E79

5 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A79) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E79.

Embodiment E80

Except for using the product (e18), Battery (A80) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E80.

Embodiment E81

Except for using the product (e19), Battery (A81) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E81.

Embodiment E82

Except for using the product (e20), Battery (A82) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E82.

Embodiment E83

Except for using the product (e21), Battery (A83) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E83.

Embodiment E84

Except for using the product (e22), Battery (A84) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E84.

Embodiment E85

Except for using the product (e23), Battery (A85) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E85.

Comparative Example E7

Except for using the product (e24), Battery (B13) has an identicalconfiguration to that of Embodiment E79. This battery was termedComparative Example E7.

Embodiment E159

Except for using the product (e25), Battery (B14) has an identicalconfiguration to that of Embodiment E79. This battery was termedEmbodiment E159.

Embodiment E86

1 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 39 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A86) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E86.

Embodiment E87

Except for using the product (e18), Battery (A87) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E87.

Embodiment E88

Except for using the product (e19), Battery (A88) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E88.

Embodiment E89

Except for using the product (e20), Battery (A89) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E89.

Embodiment E90

Except for using the product (e21), Battery (A90) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E90.

Embodiment E91

Except for using the product (e22), Battery (A91) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E91.

Embodiment E92

Except for using the product (e23), Battery (A92) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E92.

Comparative Example E8

Except for using the product (e24), Battery (B15) has an identicalconfiguration to that of Embodiment E86. This battery was termedComparative Example E8.

Embodiment E160

Except for using the product (e25), Battery (B16) has an identicalconfiguration to that of Embodiment E86. This battery was termedEmbodiment E160.

Embodiment E93

35 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A93) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E93.

Embodiment E94

20 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A94) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E94.

Embodiment E95

0.5 wt. % of the product (e17) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A95) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E95.

Embodiment E96

35 wt. % of the product (e20) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A96) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E96.

Embodiment E97

20 wt. % of the product (e20) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A97) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E97.

Embodiment E98

0.5 wt. % of the product (e20) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A98) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E98.

Embodiment E99

35 wt. % of the product (e23) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A99) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E99.

Embodiment E100

20 wt. % of the product (e23) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A100) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E100.

Embodiment E101

0.5 wt. % of the product (e23) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A101) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E101.

Embodiment E102

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e26) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 0.5 wt. % to thetotal mass of the product (e26). The number average particle size of theproduct (e26) was 0.9 μm.

5 wt. % of the product (e26) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A102) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E102.

Embodiment E103

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e27) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 1.0 wt. % to thetotal mass of the product (e27). The number average particle size of theproduct (e27) was 1.0 μm.

Except for using the product (e27), Battery (A103) has an identicalconfiguration to that of Embodiment E102. This battery was termedEmbodiment E103.

Embodiment E104

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e28) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 10.0 wt. % tothe total mass of the product (e28). The number average particle size ofthe product (e28) was 1.0 μm.

Except for using the product (e28), Battery (A104) has an identicalconfiguration to that of Embodiment E103. This battery was termedEmbodiment E104.

Embodiment E105

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e29) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 20.0 wt. % tothe total mass of the product (e29). The number average particle size ofthe product (e29) was 1.0 μm.

Except for using the product (e29), Battery (A105) has an identicalconfiguration to that of Embodiment E103. This battery was termedEmbodiment E105.

Embodiment E106

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e30) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 30.0 wt. % tothe total mass of the product (e30). The number average particle size ofthe product (e30) was 1.0 μm.

Except for using the product (e30), Battery (A106) has an identicalconfiguration to that of Embodiment E103. This battery was termedEmbodiment E106.

Embodiment E107

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e31) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 38.0 wt. % tothe total mass of the product (e31). The number average particle size ofthe product (e31) was 1.1 μm.

Except for using the product (e31), Battery (A107) has an identicalconfiguration to that of Embodiment E103. This battery was termedEmbodiment E107.

Embodiment E108

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e32) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 40.0 wt. % tothe total mass of the product (e32). The number average particle size ofthe product (e32) was 1.2 μm.

Except for using the product (e32), Battery (A108) has an identicalconfiguration to that of Embodiment E103. This battery was termedEmbodiment E108.

Comparative Example E9

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e33) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 0.1 wt. % to thetotal mass of the product (e33). The number average particle size of theproduct (e33) was 0.9 μm.

Except for using the product (e33), Battery (B17) has an identicalconfiguration to that of Embodiment E108. This battery was termedComparative Example E9.

Embodiment E161

The surface of SiO particle (t) was supported with nickel, as theelectronic conductive additive (B), by electroless plating techniquewith the use of Ni-801 (Kojundo Chemical Laboratory) as a platingsolution, so that a product (e34) was prepared. The proportion of theelectronic conductive additive (B) was determined to be 50.0 wt. % tothe total mass of the product (e34). The number average particle size ofthe product (e34) was 1.4 μm.

Except for using the product (e34), Battery (B18) has an identicalconfiguration to that of Embodiment E108. This battery was termedEmbodiment E161.

Embodiment E109

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e35)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 0.5 wt. % and 59.5 wt.%, respectively, to the total mass of the product (e35). The numberaverage particle size of the product (e35) was 15.5 μm.

30 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 10 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A109) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E109.

Embodiment E110

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e36)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 1.0 wt. % and 59.0 wt.%, respectively, to the total mass of the product (e36). The numberaverage particle size of the product (e36) was 16.3 μm.

Except for using this product (e36), Battery (A110) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E110.

Embodiment E111

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e37)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 10.0 wt. % and 50.0wt. %, respectively, to the total mass of the product (e37). The numberaverage particle size of the product (e37) was 18.3 μm.

Except for using this product (e37), Battery (A111) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E111.

Embodiment E112

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e38)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 20.0 wt. % and 40.0wt. %, respectively, to the total mass of the product (e38). The numberaverage particle size of the product (e38) was 20.0 μm.

Except for using this product (e38), Battery (A112) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E112.

Embodiment E113

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e39)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 30.0 wt. % and 30.0wt. %, respectively, to the total mass of the product (e39). The numberaverage particle size of the product (e39) was 20.3 μm.

Except for using this product (e39), Battery (A113) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E113.

Embodiment E114

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e40)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 38.0 wt. % and 22.0wt. %, respectively, to the total mass of the product (e40). The numberaverage particle size of the product (e40) was 20.7 μm.

Except for using this product (e40), Battery (A114) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E114.

Embodiment E115

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e41)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 40.0 wt. % and 20.0wt. %, respectively, to the total mass of the product (e41). The numberaverage particle size of the product (e41) was 21.7 μm.

Except for using this product (e41), Battery (A115) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E115.

Comparative Example E10

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e42)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 0.1 wt. % and 59.9 wt.%, respectively, to the total mass of the product (e42). The numberaverage particle size of the product (e42) was 14.5 μm.

Except for using this product (e42), Battery (B19) has an identicalconfiguration to that of Embodiment E109. This battery was termedComparative Example E10.

Embodiment E162

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with carbon, as the electronicconductive additive (B), using the method (CVD) of thermally decomposingtoluene gas under argon atmosphere at 1000° C., so that a product (e43)was prepared. The proportions of the electronic conductive additive (B)and the carbon material (E) were determined to be 50.0 wt. % and 10.0wt. %, respectively, to the total mass of the product (e43). The numberaverage particle size of the product (e43) was 22.5 μm.

Except for using this product (e43), Battery (B20) has an identicalconfiguration to that of Embodiment E109. This battery was termedEmbodiment E162.

Embodiment E116

10 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 30 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A116) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E116.

Embodiment E117

Except for using the product (e36), Battery (A117) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E117.

Embodiment E118

Except for using the product (e37), Battery (A118) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E118.

Embodiment E119

Except for using the product (e38), Battery (A119) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E119.

Embodiment E120

Except for using the product (e39), Battery (A120) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E120.

Embodiment E121

Except for using the product (e40), Battery (A121) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E121.

Embodiment E122

Except for using the product (e41), Battery (A122) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E122.

Comparative Example E11

Except for using the product (e42), Battery (B21) has an identicalconfiguration to that of Embodiment E116. This battery was termedComparative Example E11.

Embodiment E163

Except for using the product (e43), Battery (B22) has an identicalconfiguration to that of Embodiment E116. This battery was termedEmbodiment E163

Embodiment E123

5 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A123) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E123.

Embodiment E124

Except for using the product (e36), Battery (A124) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E124.

Embodiment E125

Except for using the product (e37), Battery (A125) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E125.

Embodiment E126

Except for using the product (e38), Battery (A126) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E126.

Embodiment E127

Except for using the product (e39), Battery (A127) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E127.

Embodiment E128

Except for using the product (e40), Battery (A128), has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E128.

Embodiment E129

Except for using the product (e41), Battery (A129) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E129.

Comparative Example E12

Except for using the product (e42), Battery (B23) has an identicalconfiguration to that of Embodiment E123. This battery was termedComparative Example E12.

Embodiment E164

Except for using the product (e43), Battery (B24) has an identicalconfiguration to that of Embodiment E123. This battery was termedEmbodiment E164

Embodiment E130

1 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 39 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A130) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E130.

Embodiment E131

Except for using the product (e36), Battery (A131) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E131.

Embodiment E132

Except for using the product (e37), Battery (A132) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E132.

Embodiment E133

Except for using the product (e38), Battery (A133) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E133.

Embodiment E134

Except for using the product (e39), Battery (A134) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E134.

Embodiment E135

Except for using the product (e40), Battery (A135) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E135.

Embodiment E136

Except for using the product (e41), Battery (A136) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E136.

Comparative Example E13

Except for using the product (e42), Battery (B25) has an identicalconfiguration to that of Embodiment E130. This battery was termedComparative Example E13.

Embodiment E165

Except for using the product (e43), Battery (B26) has an identicalconfiguration to that of Embodiment E130. This battery was termedEmbodiment E165

Embodiment E137

35 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A137) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E137.

Embodiment E138

20 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A138) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E138.

Embodiment E139

0.5 wt. % of the product (e35) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A139) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E139.

Embodiment E140

35 wt. % of the product (e38) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A140) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E140.

Embodiment E141

20 wt. % of the product (e38) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A141) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E141.

Embodiment E142

0.5 wt. % of the product (e38) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A142) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E142.

Embodiment E143

35 wt. % of the product (e41) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 5 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A143) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E143.

Embodiment E144

20 wt. % of the product (e41) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 20 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A144) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E144.

Embodiment E145

0.5 wt. % of the product (e41) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 35.5 wt. % of natural graphite and 20 wt. %of artificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A145) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E145.

Embodiment E146

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e44) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 0.5 wt. % and 59.5 wt. %, respectively, to the total mass of theproduct (e44). The number average particle size of the product (e44) was13.2 μm.

10 wt. % of the product (e44) and, as the carbon material (D), 40 wt. %of meso carbon microbeads, 30 wt. % of natural graphite and 20 wt. % ofartificial graphite were mixed together to prepare a negative activematerial. Except for the above, Battery (A146) has an identicalconfiguration to that of Embodiment E1. This battery was termedEmbodiment E146.

Embodiment E147

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e45) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 1.0 wt. % and 59.0 wt. %, respectively, to the total mass of theproduct (e45). The number average particle size of the product (e45) was14.2 μm.

Except for using this product (e45), Battery (A147) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E147.

Embodiment E148

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e46) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 10.0 wt. % and 50.0 wt. %, respectively, to the total mass of theproduct (e46). The number average particle size of the product (e46) was15.4 μm.

Except for using this product (e46), Battery (A148) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E148.

Embodiment E149

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e47) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 20.0 wt. % and 40.0 wt. %, respectively, to the total mass of theproduct (e47). The number average particle size of the product (e47) was16.7 μm.

Except for using this product (e47), Battery (A149) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E149.

Embodiment E150

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical. Laboratory) as a plating solution,so that a product (e48) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 30.0 wt. % and 30.0 wt. %, respectively, to the total mass of theproduct (e48). The number average particle size of the product (e48) was18.2 μm.

Except for using this product (e48), Battery (A150) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E150.

Embodiment E151

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e49) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 38.0 wt. % and 22.0 wt. %, respectively, to the total mass of theproduct (e49). The number average particle size of the product (e49) was19.9 μm.

Except for using this product (e49), Battery (A151) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E151.

Embodiment E152

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e50) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 40.0 wt. % and 20.0 wt. %, respectively, to the total mass of theproduct (e50). The number average particle size of the product (e50) was20.2 μm.

Except for using this product (e50), Battery (A152) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E152.

Comparative Example E14

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e51) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 0.1 wt. % and 59.9 wt. %, respectively, to the total mass of theproduct (e51). The number average particle size of the product (e51) was13.0 μm.

Except for using this product (e51), Battery (B27) has an identicalconfiguration to that of Embodiment E146. This battery was termedComparative Example E14.

Embodiment E166

By mechanochemical reaction between SiO particle (t) and artificialgraphite, as the carbon material (E), a composite was prepared. Thesurface of such composite was supported with copper, as the electronicconductive additive (B), by electroless plating technique with the useof C200LT solution (Kojundo Chemical Laboratory) as a plating solution,so that a product (e52) was prepared. The proportions of the electronicconductive additive (B) and the carbon material (E) were determined tobe 50.0 wt. % and 10.0 wt. %, respectively, to the total mass of theproduct (e52). The number average particle size of the product (e52) was21.1 μm.

Except for using this product (e52), Battery (B28) has an identicalconfiguration to that of Embodiment E146. This battery was termedEmbodiment E166.

Comparative Example E15

Except for using artificial graphite as the negative active material,Battery (B29) has an identical configuration to that of Embodiment E1.This battery was termed Comparative Example E15.

Comparative Example E16

Except for using the product (e1) as the negative active material,Battery (B30) has an identical configuration to that of Embodiment E1.This battery was termed Comparative Example E16.

<Measurement of Particle Size Distribution>

The particle size distribution described in this description wasmeasured according to the following manner. 0.1 g of sample was stirredin water and this preparation was sent to a measuring stand. With theuse of a semiconductor laser (wave length of 680 nm, and power of 3 mW)as a light source, the preparation was measured by means of laserdiffraction and laser scattering methods (SALD2000J, SHIMADZU).

<Charge/Discharge Test>

Each battery described above was charged at a current of 1 CmA (700 mA)at a temperature of 25° C. until the voltage reached 4.2 V, subsequentlycharged at a constant voltage of 4.2 V for 2 hours, and then dischargedat a current of 1 CmA until the voltage dropped to 2.0 V. These stepswere taken as one cycle, and the initial capacity and the capacityretention ratio after 500 cycles were examined.

The initial capacity described in this description means the dischargecapacity at the 1^(st) cycle, and the capacity retention ratio means theratio of the discharge capacity at the 500^(th) cycle to the one at the1^(st) cycle (expressed in percentage).

TABLE E1 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E1 Si C 0.1 0.5 702 12 EM E1 Si C 0.5 0.5 811 52 EM E2 Si C 5.0 0.5822 61 EM E3 Si C 10.0 0.5 823 63 EM E4 Si C 20.0 0.5 819 67 EM E5 Si C30.0 0.5 805 64 EM E6 Si C 38.0 0.5 798 63 EM E7 Si C 40.0 0.5 795 55 EME153 Si C 50.0 0.5 712 40In Tables E1 to E27, EM in the first column refers to Embodiment and CErefers to Comparative Example; for example, EM E1 refers to EmbodimentE1 and CE E1 refers to Comparative Example E1.

TABLE E2 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E2 Si C 0.1 20.0 687 16 EM E8 Si C 0.5 20.0 783 54 EM E9 Si C 5.020.0 794 64 EM E10 Si C 10.0 20.0 798 67 EM E11 Si C 20.0 20.0 784 70 EME12 Si C 30.0 20.0 772 69 EM E13 Si C 38.0 20.0 764 67 EM E14 Si C 40.020.0 741 57 EM E154 Si C 50.0 20.0 673 42

TABLE E3 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E15 Si C 0.5 0.1 753 50 EM E1 Si C 0.5 0.5 811 52 EM E16 Si C 0.51.0 806 65 EM E17 Si C 0.5 5.0 798 70 EM E18 Si C 0.5 10.0 794 69 EM E19Si C 0.5 15.0 789 62 EM E8 Si C 0.5 20.0 783 54 EM E20 Si C 0.5 25.0 73051

TABLE E4 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E21 Si C 20.0 0.1 739 50 EM E4 Si C 20.0 0.5 819 55 EM E22 Si C20.0 1.0 813 69 EM E23 Si C 20.0 5.0 809 72 EM E24 Si C 20.0 10.0 802 75EM E25 Si C 20.0 15.0 794 74 EM E11 Si C 20.0 20.0 786 72 EM E26 Si C20.0 25.0 730 51

TABLE E5 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E27 Si C 40.0 0.1 724 51 EM E7 Si C 40.0 0.5 795 55 EM E28 Si C40.0 1.0 790 69 EM E29 Si C 40.0 5.0 782 73 EM E30 Si C 40.0 10.0 775 75EM E31 Si C 40.0 15.0 759 68 EM E14 Si C 40.0 20.0 741 57 EM E32 Si C40.0 25.0 714 50

TABLE E6 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive [B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E3 Si C 0.1 59.9 0.5 692 32EM E33 Si C 0.5 59.5 0.5 798 63 EM E34 Si C 5.0 59.0 0.5 802 72 EM E35Si C 10.0 50.0 0.5 805 75 EM E36 Si C 20.0 40.0 0.5 799 78 EM E37 Si C30.0 30.0 0.5 785 73 EM E38 Si C 38.0 22.0 0.5 778 70 EM E39 Si C 40.020.0 0.5 776 64 EM E155 Si C 50.0 10.0 0.5 684 42

TABLE E7 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E4 Si C 0.1 59.9 20.0 66935 EM E40 Si C 0.5 59.5 20.0 764 64 EM E41 Si C 5.0 59.0 20.0 779 73 EME42 Si C 10.0 50.0 20.0 779 75 EM E43 Si C 20.0 40.0 20.0 768 79 EM E44Si C 30.0 30.0 20.0 759 74 EM E45 Si C 38.0 22.0 20.0 742 73 EM E46 Si C40.0 20.0 20.0 725 65 EM E156 Si C 50.0 10.0 20.0 659 43

TABLE E8 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E47 Si C 0.5 59.5 0.1 73160 EM E27 Si C 0.5 59.5 0.5 798 63 EM E48 Si C 0.5 59.5 1.0 792 75 EME49 Si C 0.5 59.5 5.0 785 78 EM E50 Si C 0.5 59.5 10.0 781 75 EM E51 SiC 0.5 59.5 15.0 774 69 EM E34 Si C 0.5 59.5 20.0 764 64 EM E52 Si C 0.559.5 25.0 701 58

TABLE E9 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E53 Si C 20.0 40.0 0.1 71761 EM E30 Si C 20.0 40.0 0.5 799 78 EM E54 Si C 20.0 40.0 1.0 793 79 EME55 Si C 20.0 40.0 5.0 785 80 EM E56 Si C 20.0 40.0 10.0 776 79 EM E57Si C 20.0 40.0 15.0 770 79 EM E37 Si C 20.0 40.0 20.0 768 79 EM E58 Si C20.0 40.0 25.0 715 63

TABLE E10 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E59 Si C 40.0 20.0 0.1 68958 EM E33 Si C 40.0 20.0 0.5 776 64 EM E60 Si C 40.0 20.0 1.0 773 69 EME61 Si C 40.0 20.0 5.0 763 73 EM E62 Si C 40.0 20.0 10.0 756 72 EM E63Si C 40.0 20.0 15.0 741 70 EM E40 Si C 40.0 20.0 20.0 725 65 EM E64 Si C40.0 20.0 25.0 684 52

TABLE E11 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(F) (D)/((C) + (D)) mAh% CE E5 SiO C 0.1 70.0 580 42 EM E65 SiO C 0.5 70.0 730 54 EM E66 SiO C1.0 70.0 745 72 EM E67 SiO C 10.0 70.0 749 74 EM E68 SiO C 20.0 70.0 75468 EM E69 SiO C 30.0 70.0 760 66 EM E70 SiO C 38.0 70.0 768 65 EM E71SiO C 40.0 70.0 710 56 EM E157 SiO C 50.0 70.0 630 34

TABLE E12 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D) mAh %CE E6 SiO C 0.1 90.0 590 44 EM E72 SiO C 0.5 90.0 760 56 EM E73 SiO C1.0 90.0 752 72 EM E74 SiO C 10.0 90.0 754 86 EM E75 SiO C 20.0 90.0 74975 EM E76 SiO C 30.0 90.0 739 78 EM E77 SiO C 38.0 90.0 732 77 EM E78SiO C 40.0 90.0 700 76 EM E158 SiO C 50.0 90.0 642 41

TABLE E13 Active material (G) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E7 SiO C 0.1 95.0 595 45 EM E79 SiO C 0.5 95.0 730 58 EM E80 SiO C1.0 95.0 763 75 EM E81 SiO C 10.0 95.0 769 83 EM E82 SiO C 20.0 95.0 75086 EM E83 SiO C 30.0 95.0 745 84 EM E84 SiO C 38.0 95.0 740 81 EM E85SiO C 40.0 95.0 708 77 EM E159 SiO C 50.0 95.0 645 45

TABLE E14 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E8 SiO C 0.1 99.0 598 48 EM E86 SiO C 0.5 99.0 721 62 EM E87 SiO C1.0 99.0 763 76 EM E88 SiO C 10.0 99.0 755 77 EM E89 SiO C 20.0 99.0 73080 EM E90 SiO C 30.0 99.0 729 78 EM E91 SiO C 38.0 99.0 723 75 EM E92SiO C 40.0 99.0 703 73 EM E160 SiO C 50.0 99.0 649 49

TABLE E15 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E93 SiO C 0.5 67.0 702 51 EM E53 SiO C 0.5 70.0 730 54 EM E94 SiO C0.5 80.0 745 55 EM E60 SiO C 0.5 90.0 760 56 EM E67 SiO C 0.5 95.0 73058 EM E74 SiO C 0.5 99.0 721 62 EM E95 SiO C 0.5 99.5 704 63

TABLE E16 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E96 SiO C 20 67.0 730 53 EM E56 SiO C 20.0 70.0 754 68 EM E97 SiO C20.0 80.0 755 76 EM E63 SiO C 20.0 90.0 749 75 EM E70 SiO C 20.0 95.0750 86 EM E77 SiO C 20.0 99.0 730 80 EM E98 SiO C 20.0 99.5 752 85

TABLE E17 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% EM E99 SiO C 40.0 67.0 702 51 EM E59 SiO C 40.0 70.0 710 56 EM E100SiO C 40.0 80.0 705 68 EM E66 SiO C 40.0 90.0 700 76 EM E73 SiO C 40.095.0 708 77 EM E80 SiO C 40.0 99.0 703 73 EM E101 SiO C 40.0 99.5 700 72

TABLE E18 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E9 SiO Ni 0.1 95.0 545 38 EM E84 SiO Ni 0.5 95.0 702 52 EM E85 SiONi 1.0 95.0 733 65 EM E86 SiO Ni 10.0 95.0 739 73 EM E87 SiO Ni 20.095.0 720 75 EM E88 SiO Ni 30.0 95.0 715 72 EM E89 SiO Ni 38.0 95.0 71069 EM E90 SiO Ni 40.0 95.0 705 65 EM E161 SiO Ni 50.0 95.0 602 32

TABLE E19 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E10 SiO C 0.1 59.9 70.0 56538 EM E109 SiO C 0.5 59.5 70.0 726 63 EM E110 SiO C 1.0 59.0 70.0 739 81EM E111 SiO C 10.0 50.0 70.0 740 85 EM E112 SiO C 20.0 40.0 70.0 741 74EM E113 SiO C 30.0 30.0 70.0 745 72 EM E114 SiO C 38.0 22.0 70.0 746 71EM E115 SiO C 40.0 20.0 70.0 702 65 EM E162 SiO C 50.0 10.0 70.0 615 44

TABLE E20 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E11 SiO C 0.1 59.9 90.0 68042 EM E116 SiO C 0.5 59.5 90.0 745 61 EM E117 SiO C 1.0 59.0 90.0 743 74EM E118 SiO C 10.0 50.0 90.0 740 78 EM E119 SiO C 20.0 40.0 90.0 736 82EM E120 SiO C 30.0 30.0 90.0 728 80 EM E121 SiO C 38.0 22.0 90.0 714 79EM E122 SiO C 40.0 20.0 90.0 680 78 EM E163 SiO C 50.0 10.0 90.0 673 64

TABLE E21 Active material (F) Electronic Amount of Amount of Amount ofResult conductive (B) support (E) mixture (D) mixture Initial CapacityMaterial additive wt. % wt. % wt. % capacity retention (A) (B) (B)/(F)(E)/(F) (D)/((F) + (D)) mAh ratio % CE E12 SiO C 0.1 59.9 95.0 675 40 EME123 SiO C 0.5 59.5 95.0 721 63 EM E124 SiO C 1.0 59.0 95.0 725 71 EME125 SiO C 10.0 50.0 95.0 729 77 EM E126 SiO C 20.0 40.0 95.0 732 82 EME127 SiO C 30.0 30.0 95.0 726 78 EM E128 SiO C 38.0 22.0 95.0 723 74 EME129 SiO C 40.0 20.0 95.0 719 72 EM E164 SiO C 50.0 10.0 95.0 670 63

TABLE E22 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E13 SiO C 0.1 59.9 99.0 64239 EM E130 SiO C 0.5 59.5 99.0 692 65 EM E131 SiO C 1.0 59.0 99.0 703 73EM E132 SiO C 10.0 50.0 99.0 711 78 EM E133 SiO C 20.0 40.0 99.0 719 83EM E134 SiO C 30.0 30.0 99.0 704 79 EM E135 SiO C 38.0 22.0 99.0 702 75EM E136 SiO C 40.0 20.0 99.0 698 72 EM E165 SiO C 50.0 10.0 99.0 630 68

TABLE E23 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E137 SiO C 0.5 59.5 67.0681 52 EM E91 SiO C 0.5 59.5 70.0 726 63 EM E138 SiO C 0.5 59.5 80.0 73462 EM E98 SiO C 0.5 59.5 90.0 745 61 EM E105 SiO C 0.5 59.5 95.0 721 63EM E112 SiO C 0.5 59.5 99.0 692 65 EM E139 SiO C 0.5 59.5 99.5 682 51

TABLE E24 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E140 SiO C 20.0 40.0 67.0740 58 EM E94 SiO C 20.0 40.0 70.0 741 74 EM E141 SiO C 20.0 40.0 80.0747 79 EM E101 SiO C 20.0 40.0 90.0 736 82 EM E108 SiO C 20.0 40.0 95.0732 82 EM E115 SiO C 20.0 40.0 99.0 719 83 EM E142 SiO C 20.0 40.0 99.5672 79

TABLE E25 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E) mixture (D) mixtureInitial retention Material additive wt. % wt. % wt. % capacity ratio (A)(B) (B)/(F) (E)/(F) (D)/((F) + (D)) mAh % EM E143 SiO C 40.0 20.0 67.0692 51 EM E97 SiO C 40.0 20.0 70.0 702 65 EM E144 SiO C 40.0 20.0 80.0710 74 EM E104 SiO C 40.0 20.0 90.0 680 78 EM E111 SiO C 40.0 20.0 95.0719 72 EM E118 SiO C 40.0 20.0 99.0 698 72 EM E145 SiO C 40.0 20.0 99.5681 56

TABLE E26 Active material (F) Result Electronic Amount of Amount ofAmount of Capacity conductive (B) support (E)mixture (D) mixture Initialretention Material additive wt. % wt. % wt. % capacity ratio (A) (B)(B)/(F) (E)/(F) (D)/((F) + (D)) mAh % CE E14 SiO Cu 0.1 59.9 90.0 660 41EM E146 SiO Cu 0.5 59.5 90.0 725 59 EM E147 SiO Cu 1.0 59.0 90.0 723 69EM E148 SiO Cu 10.0 50.0 90.0 720 74 EM E149 SiO Cu 20.0 40.0 90.0 71675 EM E150 SiO Cu 30.0 30.0 90.0 709 74 EM E151 SiO Cu 38.0 22.0 90.0694 72 EM E152 SiO Cu 40.0 20.0 90.0 680 71 EM E166 SiO Cu 50.0 10.090.0 632 57

TABLE E27 Active material (C) Result Electronic Amount of Amount ofCapacity conductive (B) support (D) mixture Initial retention Materialadditive wt. % wt. % capacity ratio (A) (B) (B)/(C) (D)/((C) + (D)) mAh% CE E15 C — — — 615 80 CE E16 Si C 0.5 — 820 9

INDUSTRIAL APPLICABILITY

The present invention provides a secondary battery which has a largedischarge capacity as well as satisfactory cycle performance.

What is claimed is:
 1. A non-aqueous electrolyte secondary batterycomprising: a positive electrode; a negative electrode having a negativeactive material; and a non-aqueous electrolyte; characterized in thatsaid negative active material contains composite particle (C), which hassilicon-containing particle (A) and electronic conductive additive (B),said silicon-containing particle (A) has a content of carbon, and whenmeasured at a temperature rising rate of 10±2° C./min bythermogravimetry, said composite particle (C) exhibits two stages ofweight loss in the range of 30 to 1000° C.
 2. The non-aqueouselectrolyte secondary battery according to claim 1, wherein weight lossstarts in thermogravimetry of the composite particle (C) at atemperature of not higher than 600° C. at the first stage and at atemperature of higher than 600° C. at the second stage.
 3. Thenon-aqueous electrolyte secondary battery according to claim 1, whereinthe proportion of weight loss to the weight prior to the temperaturerise in thermogravimetry of the composite particle (C) is within a rangeof 3 to 30 wt. % at the first stage and 5 to 65 wt. % at the secondstage.
 4. The non-aqueous electrolyte secondary battery according toclaim 2, wherein the proportion of weight loss to the weight prior tothe temperature rise in thermogravimetry of the composite particle (C)is within a range of 3 to 30 wt. % at the first stage and 5 to 65 wt. %at the second stage.
 5. The non-aqueous electrolyte secondary batteryaccording to claim 1, wherein weight loss starts in thermogravimetry ofthe negative active material at a temperature of not lower than 350° C.at the first stage and at a temperature of not higher than 800° C. atthe second stage.
 6. The non-aqueous electrolyte secondary batteryaccording to claim 2, wherein weight loss starts in thermogravimetry ofthe negative active material at a temperature of not lower than 350° C.at the first stage and at a temperature of not higher than 800° C. atthe second stage.
 7. The non-aqueous electrolyte secondary batteryaccording to claim 3, wherein weight loss starts in thermogravimetry ofthe negative active material at a temperature of not lower than 350° C.at the first stage and at a temperature of not higher than 800° C. atthe second stage.
 8. The non-aqueous electrolyte secondary batteryaccording to claim 4, wherein weight loss starts in thermogravimetry ofthe negative active material at a temperature of not lower than 350° C.at the first stage and at a temperature of not higher than 800° C. atthe second stage.